ASVAB Auto and Shop Information (AS) Practice Test (2026)

ASVAB Electronics Information (EI) Practice Test 2026

ASVAB Electronics Information (EI) Practice Test (2026) covers ASVAB Electronics Information (EI) practice test in a four-choice format with a “Show Answer” toggle for review. Each item includes the correct answer, a concise explanation, and official citations where applicable so you can verify what the test is targeting. Use it to practice circuits, symbols, tools, basic components, and practical electronics terms.

FAQ

What should I know for ASVAB Electronics Information (EI) on the ASVAB?

Focus on the recurring concepts that appear in many forms, not one-off trivia. Learn the key terms, practice mixed sets, and use explanations to build a quick recognition habit so you don’t overthink simple items.

What is Electronics Information (EI) on the ASVAB?

It measures practical knowledge in context—recognizing terms, concepts, and correct applications the way they appear in short, real-world questions. The key is understanding the underlying idea well enough to eliminate close distractors.

What is Electronics Information (EI) on the ASVAB (part 2)?

What should I know for ASVAB Electronics Information (EI) on the ASVAB (part 2)?

How many ASVAB Electronics Information questions are on the ASVAB?

It varies by test format and form, but this subtest is timed and rewards pacing. Plan for a few dozen questions and practice moving on when one is taking too long, then return if time remains.

ASVAB Auto Shop Practice Test (AS) — Practice Questions and Answers

Q001. A circuit has 12 V across a 6 Ω resistor. What is the current through the resistor?

Correct Answer: B
Explanation: Ohm’s law: I = V/R = 12/6 = 2 A.
Citation: ASVAB content domain — Electronics Information; underlying principle: Ohm’s law (I = V/R).

Q002. Two resistors, 4 Ω and 8 Ω, are connected in series. What is the total resistance?

Correct Answer: B
Explanation: Series resistances add: 4 + 8 = 12 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: series resistance addition.

Q003. Two resistors, 6 Ω and 3 Ω, are connected in parallel. What is the equivalent resistance?

Correct Answer: A
Explanation: Parallel: 1/R = 1/6 + 1/3 = 1/2, so R = 2 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: parallel resistance (reciprocal sum).

Q004. A 9 V battery powers a device drawing 0.5 A. Approximately how much power is used?

Correct Answer: A
Explanation: Power P = VI = 9 × 0.5 = 4.5 W.
Citation: ASVAB content domain — Electronics Information; underlying principle: electrical power (P = VI).

Q005. If voltage across a fixed resistor is doubled, the current through it will:

Correct Answer: B
Explanation: With constant resistance, I = V/R, so doubling V doubles I.
Citation: ASVAB content domain — Electronics Information; underlying principle: linear V–I relationship for resistors.

Q006. Which device is designed primarily to allow current to flow in only one direction?

Correct Answer: B
Explanation: A diode conducts forward and blocks reverse (ideally).
Citation: ASVAB content domain — Electronics Information; underlying principle: diode rectification.

Q007. In a basic LED circuit, which component is most commonly added in series to limit current?

Correct Answer: B
Explanation: A series resistor drops voltage and limits LED current.
Citation: ASVAB content domain — Electronics Information; underlying principle: current limiting with resistors.

Q008. A capacitor’s stored energy increases most directly when its:

Correct Answer: B
Explanation: Energy stored is U = ½CV², so increasing V raises energy strongly.
Citation: ASVAB content domain — Electronics Information; underlying principle: capacitor energy (½CV²).

Q009. Which quantity is measured in coulombs (C)?

Correct Answer: B
Explanation: The coulomb is the SI unit of electric charge.
Citation: ASVAB content domain — Electronics Information; underlying principle: electric charge units.

Q010. A 10 µF capacitor is connected to a 5 V source. Approximately how much charge does it store?

Correct Answer: B
Explanation: Q = CV = 10 µF × 5 V = 50 µC.
Citation: ASVAB content domain — Electronics Information; underlying principle: capacitor charge (Q = CV).

Q011. Which component opposes changes in current and stores energy in a magnetic field?

Correct Answer: C
Explanation: Inductors resist current change and store energy magnetically.
Citation: ASVAB content domain — Electronics Information; underlying principle: inductance and magnetic energy storage.

Q012. AC voltage is stepped up most directly using a:

Correct Answer: B
Explanation: Transformers use mutual induction to change AC voltage levels.
Citation: ASVAB content domain — Electronics Information; underlying principle: transformer action (mutual induction).

Q013. A transformer has 200 primary turns and 50 secondary turns. If 120 V AC is applied to the primary, the secondary voltage is closest to:

Correct Answer: A
Explanation: V_s/V_p = N_s/N_p = 50/200 = 1/4, so V_s = 30 V.
Citation: ASVAB content domain — Electronics Information; underlying principle: transformer turns ratio.

Q014. Which instrument is typically used to measure electrical resistance directly?

Correct Answer: C
Explanation: An ohmmeter measures resistance (often within a multimeter).
Citation: ASVAB content domain — Electronics Information; underlying principle: basic electrical measurement instruments.

Q015. In a series circuit, if one component opens (fails open), what happens to current in the circuit?

Correct Answer: C
Explanation: A series circuit needs a complete path; an open makes current zero.
Citation: ASVAB content domain — Electronics Information; underlying principle: series circuit continuity.

Q016. Which waveform is characterized by a single frequency with smooth periodic oscillation?

Correct Answer: C
Explanation: A sine wave is the fundamental smooth periodic waveform.
Citation: ASVAB content domain — Electronics Information; underlying principle: AC waveform basics.

Q017. Frequency is measured in:

Correct Answer: B
Explanation: Hertz (Hz) is cycles per second.
Citation: ASVAB content domain — Electronics Information; underlying principle: frequency units.

Q018. A 60 Hz AC signal completes how many cycles in 2 seconds?

Correct Answer: C
Explanation: Cycles = frequency × time = 60 × 2 = 120 cycles.
Citation: ASVAB content domain — Electronics Information; underlying principle: frequency-time relationship.

Q019. Which material is generally a good electrical conductor?

Correct Answer: C
Explanation: Metals like copper conduct well due to free electrons.
Citation: ASVAB content domain — Electronics Information; underlying principle: conductors vs insulators.

Q020. A fuse in a circuit is intended to protect equipment primarily by:

Correct Answer: B
Explanation: A fuse opens the circuit when current exceeds its rating.
Citation: ASVAB content domain — Electronics Information; underlying principle: overcurrent protection.

Q021. If a circuit draws 3 A from a 120 V source, how much electrical power is consumed?

Correct Answer: C
Explanation: P = VI = 120 × 3 = 360 W.
Citation: ASVAB content domain — Electronics Information; underlying principle: power calculation (P = VI).

Q022. Which term describes opposition to current flow in an AC circuit due to capacitors or inductors?

Correct Answer: B
Explanation: Reactance is the frequency-dependent opposition from capacitors/inductors.
Citation: ASVAB content domain — Electronics Information; underlying principle: AC reactance concept.

Q023. In a simple RC circuit, increasing capacitance (with R fixed) will generally:

Correct Answer: B
Explanation: Time constant τ = RC; increasing C increases τ.
Citation: ASVAB content domain — Electronics Information; underlying principle: RC time constant.

Q024. A silicon diode typically drops about how much voltage when forward-biased at moderate current?

Correct Answer: B
Explanation: A common approximation for silicon diode forward drop is about 0.7 V.
Citation: ASVAB content domain — Electronics Information; underlying principle: diode forward voltage (silicon).

Q025. In a typical NPN transistor used as a switch, a small base current primarily allows a larger current to flow between:

Correct Answer: B
Explanation: In an NPN transistor, base drive controls a much larger collector-to-emitter current.
Citation: ASVAB content domain — Electronics Information; underlying principle: transistor current control (switching/amplification).

Q026. A 8 Ω resistor is connected across 24 V DC. What current flows and what power is dissipated (closest)?

Correct Answer: A
Explanation: First find current: I = V/R = 24/8 = 3.0 A. Then power: P = VI = 24×3.0 = 72 W (equivalently V²/R).
Citation: ASVAB content domain — Electronics Information; underlying principle: Ohm’s law and power (I = V/R, P = VI).

Q027. Three resistors 5 Ω, 7 Ω, and 8 Ω are in series across 20 V. What is the circuit current (closest)?

Correct Answer: A
Explanation: Series resistance adds: R_total = 5+7+8 = 20 Ω. Current I = V/R_total = 20/20 ≈ 1.00 A.
Citation: ASVAB content domain — Electronics Information; underlying principle: series resistance and Ohm’s law.

Q028. Resistors 6 Ω, 12 Ω, and 24 Ω are connected in parallel. The equivalent resistance is closest to:

Correct Answer: A
Explanation: For parallel resistors, 1/R_eq = 1/6 + 1/12 + 1/24 = 4/24 + 2/24 + 1/24 = 7/24, so R_eq = 24/7 ≈ 3.43 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: parallel resistance (reciprocal sum).

Q029. A voltage divider has 3 kΩ on top and 6 kΩ on bottom across 18 V. What is the output voltage across the bottom resistor?

Correct Answer: A
Explanation: V_out = V_in × R_bottom/(R_top+R_bottom) = 18×6000/(3000+6000) = 18×(2/3) = 12.0 V.
Citation: ASVAB content domain — Electronics Information; underlying principle: voltage divider (series resistors).

Q030. On a resistor color code, what does the tolerance band indicate?

Correct Answer: B
Explanation: The tolerance band specifies how far the actual resistance may vary from the stated nominal value (e.g., ±5%).
Citation: ASVAB content domain — Electronics Information; underlying principle: resistor tolerance concept.

Q031. A 22 µF capacitor is charged to 9 V. Approximately how much charge is stored?

Correct Answer: A
Explanation: Q = CV. Using µF×V gives µC: Q ≈ 22×9 = 198 µC.
Citation: ASVAB content domain — Electronics Information; underlying principle: capacitor charge (Q = CV).

Q032. A 47 µF capacitor is charged to 12 V. Approximately how much energy is stored?

Correct Answer: A
Explanation: Energy in a capacitor is U = ½CV² = 0.5×47×10⁻⁶×12² ≈ 0.003384 J = 3.38 mJ.
Citation: ASVAB content domain — Electronics Information; underlying principle: capacitor energy (½CV²).

Q033. An inductor of 20 mH carries 3 A. Approximately how much magnetic energy is stored?

Correct Answer: A
Explanation: Inductor energy is U = ½LI² = 0.5×0.020×3² = 0.5×0.020×9 = 0.09 J.
Citation: ASVAB content domain — Electronics Information; underlying principle: inductor energy (½LI²).

Q034. An inductor of 15 mH is used at 400 Hz. Its inductive reactance is closest to:

Correct Answer: A
Explanation: X_L = 2πfL = 2π×400×0.015 ≈ 37.7 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: inductive reactance (X_L = 2πfL).

Q035. A 0.10 µF capacitor is used at 1,000 Hz. Its capacitive reactance is closest to:

Correct Answer: A
Explanation: X_C = 1/(2πfC) = 1/(2π×1000×0.10×10⁻⁶) ≈ 1592 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: capacitive reactance (X_C = 1/(2πfC)).

Q036. If the frequency of an AC signal increases while capacitance stays constant, capacitive reactance X_C will:

Correct Answer: B
Explanation: X_C = 1/(2πfC). As frequency f increases, the denominator increases, so X_C decreases.
Citation: ASVAB content domain — Electronics Information; underlying principle: frequency dependence of capacitive reactance.

Q037. If the frequency of an AC signal increases while inductance stays constant, inductive reactance X_L will:

Correct Answer: A
Explanation: X_L = 2πfL, so it increases directly with frequency.
Citation: ASVAB content domain — Electronics Information; underlying principle: frequency dependence of inductive reactance.

Q038. For a sine-wave AC source, “RMS voltage” is most directly useful because it equals the DC voltage that would produce the same:

Correct Answer: C
Explanation: RMS is defined so that P = V_rms²/R matches the heating effect of an equivalent DC voltage on a resistor.
Citation: ASVAB content domain — Electronics Information; underlying principle: RMS equivalence for resistive power.

Q039. A silicon diode is placed in series with a 5 V supply feeding a resistor. When forward-biased, the diode will most commonly cause the resistor’s voltage to be approximately:

Correct Answer: B
Explanation: A forward-biased silicon diode typically drops about 0.7 V, reducing the voltage available to the resistor by that amount.
Citation: ASVAB content domain — Electronics Information; underlying principle: diode forward drop (silicon approximation).

Q040. In a basic LED circuit, the LED will not light if it is installed backward because it is:

Correct Answer: B
Explanation: An LED is a diode; reverse bias blocks current (until breakdown), so the LED will not conduct normally.
Citation: ASVAB content domain — Electronics Information; underlying principle: diode polarity (forward vs reverse bias).

Q041. Three identical LEDs are wired in series with one current-limiting resistor. Compared with using one LED (same supply), the series string will generally require:

Correct Answer: A
Explanation: Series LEDs drop more total voltage, so the resistor must drop less voltage for the same current, meaning a smaller resistance is needed (within safe design limits).
Citation: ASVAB content domain — Electronics Information; underlying principle: series voltage drops and current limiting.

Q042. Two identical resistors are connected in parallel across the same DC source. Compared with one resistor alone, the source current will be:

Correct Answer: C
Explanation: Parallel halves the equivalent resistance, so I = V/R increases to about twice for identical resistors.
Citation: ASVAB content domain — Electronics Information; underlying principle: parallel circuits and equivalent resistance.

Q043. A resistor’s wattage rating specifies the maximum:

Correct Answer: C
Explanation: The wattage rating indicates how much heat (power) the resistor can handle without overheating or failing.
Citation: ASVAB content domain — Electronics Information; underlying principle: resistor power dissipation limits.

Q044. A standard iron-core transformer will not properly step up a pure DC voltage because transformers require:

Correct Answer: B
Explanation: Transformer action depends on changing flux (AC or switching). Steady DC creates no changing magnetic field after transients.
Citation: ASVAB content domain — Electronics Information; underlying principle: transformer requires changing flux (Faraday’s law).

Q045. A transformer has 300 primary turns and 75 secondary turns. With 240 V AC on the primary, the secondary voltage is closest to:

Correct Answer: A
Explanation: Voltage ratio follows turns ratio: V_s/V_p = N_s/N_p = 75/300 = 0.25, so V_s ≈ 240×0.25 = 60 V.
Citation: ASVAB content domain — Electronics Information; underlying principle: transformer turns ratio (V proportional to turns).

Q046. A fuse is placed in series with a circuit. Under normal operation it should behave like:

Correct Answer: B
Explanation: A properly sized fuse adds minimal resistance; it opens only when current exceeds its rating.
Citation: ASVAB content domain — Electronics Information; underlying principle: overcurrent protection (fuse operation).

Q047. In many DC circuits, “ground” is best described as:

Correct Answer: B
Explanation: Ground is often a reference point (0 V) for measuring other node voltages; it may or may not be tied to earth ground.
Citation: ASVAB content domain — Electronics Information; underlying principle: voltage reference (ground) concept.

Q048. Which statement best distinguishes AC from DC in terms of frequency?

Correct Answer: B
Explanation: AC varies and alternates over time (nonzero frequency). Ideal DC is constant, equivalent to 0 Hz.
Citation: ASVAB content domain — Electronics Information; underlying principle: time-varying signals and frequency.

Q049. A capacitor placed in series with a signal line is commonly used to block:

Correct Answer: B
Explanation: A capacitor’s reactance is very high at DC (f=0), so it blocks DC but can pass changing (AC) signals depending on frequency.
Citation: ASVAB content domain — Electronics Information; underlying principle: capacitive coupling (blocking DC).

Q050. An inductor placed in series with a power line is commonly used to reduce high-frequency noise because an inductor’s reactance:

Correct Answer: B
Explanation: Inductive reactance X_L = 2πfL rises with frequency, so it impedes high-frequency noise more than low-frequency current.
Citation: ASVAB content domain — Electronics Information; underlying principle: inductive reactance increases with frequency.

Q051. A current of 1.10 A flows through a 5 Ω resistor. Approximately how much power is dissipated?

Correct Answer: A
Explanation: Power is P = I²R = (1.10)²×5 ≈ 6.05 W.
Citation: ASVAB content domain — Electronics Information; underlying principle: power in resistors (P = I²R).

Q052. Two resistors 3 Ω and 12 Ω are in series across 24 V. What is the voltage drop across the 3 Ω resistor (closest)?

Correct Answer: A
Explanation: Series current I = V/(R1+R2) = 24/(3+12) ≈ 1.60 A. Then V_R1 = IR1 ≈ 4.80 V.
Citation: ASVAB content domain — Electronics Information; underlying principle: series circuits (voltage division via IR drops).

Q053. Resistors 5 Ω and 7 Ω are connected in parallel across 15 V. What is the total current drawn (closest)?

Correct Answer: A
Explanation: Each branch has 15 V. I1 = 15/5 ≈ 3.00 A and I2 = 15/7 ≈ 2.14 A. Total is 5.14 A.
Citation: ASVAB content domain — Electronics Information; underlying principle: parallel circuits (branch currents add).

Q054. Two capacitors, 12 µF and 18 µF, are connected in series. The equivalent capacitance is closest to:

Correct Answer: A
Explanation: C_eq = (C1·C2)/(C1+C2) = (12·18)/(30) ≈ 7.20 µF.
Citation: ASVAB content domain — Electronics Information; underlying principle: series capacitance (reciprocal sum).

Q055. An inductor of 14 mH is used at 380 Hz. Its inductive reactance X_L is closest to:

Correct Answer: A
Explanation: X_L = 2πfL. L = 14 mH = 0.014 H, so X_L ≈ 33.43 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: inductive reactance (X_L = 2πfL).

Q056. A capacitor of 0.52 µF is used at 355 Hz. Its capacitive reactance X_C is closest to:

Correct Answer: A
Explanation: X_C = 1/(2πfC). With C = 0.52 µF, X_C ≈ 862 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: capacitive reactance (X_C = 1/(2πfC)).

Q057. An ideal transformer has 400 primary turns and 50 secondary turns. If primary current is 0.98 A, the secondary current is closest to:

Correct Answer: A
Explanation: I_s/I_p = N_p/N_s, so I_s = 0.98×(400/50) ≈ 7.84 A.
Citation: ASVAB content domain — Electronics Information; underlying principle: ideal transformer current ratio (inverse turns).

Q058. In a full-wave rectified DC supply, the capacitor connected across the load mainly serves to:

Correct Answer: B
Explanation: The capacitor charges near waveform peaks and then supplies current between peaks, reducing ripple.
Citation: ASVAB content domain — Electronics Information; underlying principle: filter capacitor smoothing (reducing ripple).

Q059. A Zener diode is most commonly used in circuits to provide:

Correct Answer: B
Explanation: A Zener holds near-constant voltage in reverse breakdown, making it useful as a reference/regulator.
Citation: ASVAB content domain — Electronics Information; underlying principle: Zener breakdown for voltage reference.

Q060. In a low-side NPN transistor switch, the load is typically connected between the supply and which terminal?

Correct Answer: B
Explanation: In a low-side NPN switch, the collector connects to the load and the emitter connects to ground.
Citation: ASVAB content domain — Electronics Information; underlying principle: BJT switch wiring (load at collector).

Q061. A MOSFET used as an electronic switch is controlled primarily by:

Correct Answer: A
Explanation: MOSFETs are voltage-controlled; gate-to-source voltage sets conduction with minimal steady gate current.
Citation: ASVAB content domain — Electronics Information; underlying principle: MOSFET gate-to-source voltage control.

Q062. A digital clock signal has frequency 3053 Hz. Its period is closest to:

Correct Answer: A
Explanation: Period T = 1/f. For f = 3053 Hz, T = 1/3053 s = 0.0003 s = 0.33 ms.
Citation: ASVAB content domain — Electronics Information; underlying principle: frequency–period relationship (T = 1/f).

Q063. A current of 1.70 A flows through a 6 Ω resistor. Approximately how much power is dissipated?

Correct Answer: A
Explanation: Power is P = I²R = (1.70)²×6 ≈ 17.34 W.
Citation: ASVAB content domain — Electronics Information; underlying principle: power in resistors (P = I²R).

Q064. Two resistors 8 Ω and 15 Ω are in series across 24 V. What is the voltage drop across the 8 Ω resistor (closest)?

Correct Answer: A
Explanation: Series current I = V/(R1+R2) = 24/(8+15) ≈ 1.04 A. Then V_R1 = IR1 ≈ 8.35 V.
Citation: ASVAB content domain — Electronics Information; underlying principle: series circuits (voltage division via IR drops).

Q065. Resistors 9 Ω and 9 Ω are connected in parallel across 15 V. What is the total current drawn (closest)?

Correct Answer: A
Explanation: Each branch has 15 V. I1 = 15/9 ≈ 1.67 A and I2 = 15/9 ≈ 1.67 A. Total is 3.33 A.
Citation: ASVAB content domain — Electronics Information; underlying principle: parallel circuits (branch currents add).

Q066. Two capacitors, 16 µF and 30 µF, are connected in series. The equivalent capacitance is closest to:

Correct Answer: A
Explanation: C_eq = (C1·C2)/(C1+C2) = (16·30)/(46) ≈ 10.43 µF.
Citation: ASVAB content domain — Electronics Information; underlying principle: series capacitance (reciprocal sum).

Q067. An inductor of 38 mH is used at 860 Hz. Its inductive reactance X_L is closest to:

Correct Answer: A
Explanation: X_L = 2πfL. L = 38 mH = 0.038 H, so X_L ≈ 205.33 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: inductive reactance (X_L = 2πfL).

Q068. A capacitor of 1.24 µF is used at 775 Hz. Its capacitive reactance X_C is closest to:

Correct Answer: A
Explanation: X_C = 1/(2πfC). With C = 1.24 µF, X_C ≈ 166 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: capacitive reactance (X_C = 1/(2πfC)).

Q069. An ideal transformer has 700 primary turns and 50 secondary turns. If primary current is 1.34 A, the secondary current is closest to:

Correct Answer: A
Explanation: I_s/I_p = N_p/N_s, so I_s = 1.34×(700/50) ≈ 18.76 A.
Citation: ASVAB content domain — Electronics Information; underlying principle: ideal transformer current ratio (inverse turns).

Q070. In a rectifier + capacitor power supply, the filter capacitor’s main job is to:

Q071. In a simple regulator circuit, a Zener diode is used primarily to create:

Q072. For an NPN transistor used as a low-side switch, the load is usually placed at the:

Q073. For a MOSFET switch, conduction is mainly set by the:

Q074. A digital clock signal has frequency 4529 Hz. Its period is closest to:

Correct Answer: A
Explanation: Period T = 1/f. For f = 4529 Hz, T = 1/4529 s = 0.0002 s = 0.22 ms.
Citation: ASVAB content domain — Electronics Information; underlying principle: frequency–period relationship (T = 1/f).

Q075. A current of 2.30 A flows through a 7 Ω resistor. Approximately how much power is dissipated?

Correct Answer: A
Explanation: Power is P = I²R = (2.30)²×7 ≈ 37.03 W.
Citation: ASVAB content domain — Electronics Information; underlying principle: power in resistors (P = I²R).

Q076. Two resistors 6 Ω and 18 Ω are in series across 24 V. What is the voltage drop across the 6 Ω resistor (closest)?

Correct Answer: A
Explanation: Series current I = V/(R1+R2) = 24/(6+18) ≈ 1.00 A. Then V_R1 = IR1 ≈ 6.00 V.
Citation: ASVAB content domain — Electronics Information; underlying principle: series circuits (voltage division via IR drops).

Q077. Resistors 5 Ω and 11 Ω are connected in parallel across 15 V. What is the total current drawn (closest)?

Correct Answer: A
Explanation: Each branch has 15 V. I1 = 15/5 ≈ 3.00 A and I2 = 15/11 ≈ 1.36 A. Total is 4.36 A.
Citation: ASVAB content domain — Electronics Information; underlying principle: parallel circuits (branch currents add).

Q078. Two capacitors, 20 µF and 18 µF, are connected in series. The equivalent capacitance is closest to:

Correct Answer: A
Explanation: C_eq = (C1·C2)/(C1+C2) = (20·18)/(38) ≈ 9.47 µF.
Citation: ASVAB content domain — Electronics Information; underlying principle: series capacitance (reciprocal sum).

Q079. An inductor of 62 mH is used at 1340 Hz. Its inductive reactance X_L is closest to:

Correct Answer: A
Explanation: X_L = 2πfL. L = 62 mH = 0.062 H, so X_L ≈ 522.01 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: inductive reactance (X_L = 2πfL).

Q080. A capacitor of 1.96 µF is used at 1195 Hz. Its capacitive reactance X_C is closest to:

Correct Answer: A
Explanation: X_C = 1/(2πfC). With C = 1.96 µF, X_C ≈ 68 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: capacitive reactance (X_C = 1/(2πfC)).

Q081. An ideal transformer has 1000 primary turns and 50 secondary turns. If primary current is 1.70 A, the secondary current is closest to:

Correct Answer: A
Explanation: I_s/I_p = N_p/N_s, so I_s = 1.70×(1000/50) ≈ 34.00 A.
Citation: ASVAB content domain — Electronics Information; underlying principle: ideal transformer current ratio (inverse turns).

Q082. A large electrolytic capacitor placed after a bridge rectifier is primarily used to:

Q083. A Zener diode is valuable in electronics because it can act as:

Q084. In a common low-side NPN switching circuit, the load connects to the transistor’s:

Q085. A key reason MOSFETs are popular switches is that they are controlled by:

Q086. A digital clock signal has frequency 6005 Hz. Its period is closest to:

Correct Answer: A
Explanation: Period T = 1/f. For f = 6005 Hz, T = 1/6005 s = 0.0002 s = 0.17 ms.
Citation: ASVAB content domain — Electronics Information; underlying principle: frequency–period relationship (T = 1/f).

Q087. A current of 2.90 A flows through a 8 Ω resistor. Approximately how much power is dissipated?

Correct Answer: A
Explanation: Power is P = I²R = (2.90)²×8 ≈ 67.28 W.
Citation: ASVAB content domain — Electronics Information; underlying principle: power in resistors (P = I²R).

Q088. Two resistors 4 Ω and 12 Ω are in series across 24 V. What is the voltage drop across the 4 Ω resistor (closest)?

Correct Answer: A
Explanation: Series current I = V/(R1+R2) = 24/(4+12) ≈ 1.50 A. Then V_R1 = IR1 ≈ 6.00 V.
Citation: ASVAB content domain — Electronics Information; underlying principle: series circuits (voltage division via IR drops).

Q089. Resistors 9 Ω and 13 Ω are connected in parallel across 15 V. What is the total current drawn (closest)?

Correct Answer: A
Explanation: Each branch has 15 V. I1 = 15/9 ≈ 1.67 A and I2 = 15/13 ≈ 1.15 A. Total is 2.82 A.
Citation: ASVAB content domain — Electronics Information; underlying principle: parallel circuits (branch currents add).

Q090. Two capacitors, 24 µF and 30 µF, are connected in series. The equivalent capacitance is closest to:

Correct Answer: A
Explanation: C_eq = (C1·C2)/(C1+C2) = (24·30)/(54) ≈ 13.33 µF.
Citation: ASVAB content domain — Electronics Information; underlying principle: series capacitance (reciprocal sum).

Q091. An inductor of 86 mH is used at 1820 Hz. Its inductive reactance X_L is closest to:

Correct Answer: A
Explanation: X_L = 2πfL. L = 86 mH = 0.086 H, so X_L ≈ 983.44 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: inductive reactance (X_L = 2πfL).

Q092. A capacitor of 2.68 µF is used at 1615 Hz. Its capacitive reactance X_C is closest to:

Correct Answer: A
Explanation: X_C = 1/(2πfC). With C = 2.68 µF, X_C ≈ 37 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: capacitive reactance (X_C = 1/(2πfC)).

Q093. An ideal transformer has 1300 primary turns and 50 secondary turns. If primary current is 2.06 A, the secondary current is closest to:

Correct Answer: A
Explanation: I_s/I_p = N_p/N_s, so I_s = 2.06×(1300/50) ≈ 53.56 A.
Citation: ASVAB content domain — Electronics Information; underlying principle: ideal transformer current ratio (inverse turns).

Q094. In a DC supply made from rectified AC, the smoothing capacitor mainly reduces:

Q095. When reverse-biased into breakdown, a Zener diode is typically used as a:

Q096. When wiring an NPN as a low-side switch, the load is normally tied to the:

Q097. A MOSFET turns on mainly when sufficient ______ is applied.

Correct Answer: A
Explanation: A MOSFET turns on when V_GS exceeds threshold enough to form a conducting channel.
Citation: ASVAB content domain — Electronics Information; underlying principle: MOSFET threshold and V_GS control.

Q098. A digital clock signal has frequency 7481 Hz. Its period is closest to:

Correct Answer: A
Explanation: Period T = 1/f. For f = 7481 Hz, T = 1/7481 s = 0.0001 s = 0.13 ms.
Citation: ASVAB content domain — Electronics Information; underlying principle: frequency–period relationship (T = 1/f).

Q099. A current of 3.50 A flows through a 9 Ω resistor. Approximately how much power is dissipated?

Correct Answer: A
Explanation: Power is P = I²R = (3.50)²×9 ≈ 110.25 W.
Citation: ASVAB content domain — Electronics Information; underlying principle: power in resistors (P = I²R).

Q100. Two resistors 2 Ω and 15 Ω are in series across 24 V. What is the voltage drop across the 2 Ω resistor (closest)?

Correct Answer: A
Explanation: Series current I = V/(R1+R2) = 24/(2+15) ≈ 1.41 A. Then V_R1 = IR1 ≈ 2.82 V.
Citation: ASVAB content domain — Electronics Information; underlying principle: series circuits (voltage division via IR drops).

Q101. A 12 Ω load is connected across 30 V DC. Which pair is closest to the current and power?

Correct Answer: A
Explanation: Use Ohm’s law: I = V/R = 30/12 = 2.50 A. Power is P = VI = 30×2.50 ≈ 75 W (also V²/R).
Citation: ASVAB content domain — Electronics Information; underlying principle: Ohm’s law and power (I = V/R, P = VI).

Q102. A 10 Ω resistor is in series with two 20 Ω resistors in parallel. The total resistance is closest to:

Correct Answer: A
Explanation: First combine the parallel pair: R_parallel = (20||20) = 10 Ω. Then add series: R_total = 10 + 10 = 20 Ω (≈ 20 Ω).
Citation: ASVAB content domain — Electronics Information; underlying principle: series/parallel resistance reduction.

Q103. A voltage divider has 2 kΩ on top and 3 kΩ on bottom across 15 V. What is the output voltage across the bottom resistor?

Correct Answer: A
Explanation: V_out = V_in × R_bottom/(R_top+R_bottom) = 15×3000/(2000+3000) = 15×0.6 = 9.0 V.
Citation: ASVAB content domain — Electronics Information; underlying principle: voltage divider (series resistors).

Q104. A sine-wave source is 120 V RMS. The peak voltage is closest to:

Correct Answer: A
Explanation: For a sine wave, V_pk = V_rms·√2 = 120×1.414 ≈ 170 V.
Citation: ASVAB content domain — Electronics Information; underlying principle: RMS-to-peak conversion (sine wave).

Q105. A simple RC low-pass filter uses R = 10 kΩ and C = 0.01 µF. The cutoff frequency is closest to:

Correct Answer: A
Explanation: Cutoff f_c = 1/(2πRC). Here RC = 10,000×0.01×10⁻⁶ = 1.0×10⁻⁴ s, so f_c ≈ 1/(2π×1e-4) ≈ 1592 Hz.
Citation: ASVAB content domain — Electronics Information; underlying principle: RC filter cutoff (f_c = 1/(2πRC)).

Q106. A capacitor placed in series with an audio signal line is mainly used to:

Correct Answer: B
Explanation: At DC (0 Hz), a capacitor’s reactance is extremely high, so it blocks DC. For changing signals, it can pass current depending on frequency.
Citation: ASVAB content domain — Electronics Information; underlying principle: capacitive coupling (blocking DC).

Q107. An inductor of 50 mH carries 2.0 A. Approximately how much energy is stored in its magnetic field?

Correct Answer: A
Explanation: Inductor energy U = ½LI² = 0.5×0.050×(2.0)² = 0.10 J.
Citation: ASVAB content domain — Electronics Information; underlying principle: inductor energy (½LI²).

Q108. A 2.2 µF capacitor is used at 500 Hz. Its capacitive reactance is closest to:

Correct Answer: A
Explanation: X_C = 1/(2πfC) = 1/(2π×500×2.2×10⁻⁶) ≈ 145 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: capacitive reactance (X_C = 1/(2πfC)).

Q109. An inductor of 10 mH is used at 1,000 Hz. Its inductive reactance is closest to:

Correct Answer: A
Explanation: X_L = 2πfL = 2π×1000×0.010 ≈ 62.8 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: inductive reactance (X_L = 2πfL).

Q110. A 12 V supply powers an LED that drops about 2.0 V at 20 mA. The series resistor value is closest to:

Correct Answer: A
Explanation: Resistor must drop 12−2 = 10 V at 0.020 A, so R = V/I = 10/0.020 = 500 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: current limiting with series resistor.

Q111. A bridge rectifier converts AC to pulsating DC using:

Correct Answer: C
Explanation: A full-wave bridge rectifier uses four diodes so both half-cycles produce the same output polarity.
Citation: ASVAB content domain — Electronics Information; underlying principle: full-wave bridge rectification.

Q112. In an AC circuit containing a capacitor, the current through an ideal capacitor leads the capacitor’s voltage by approximately:

Correct Answer: B
Explanation: For an ideal capacitor, current leads voltage by 90° because the current is proportional to the rate of change of voltage.
Citation: ASVAB content domain — Electronics Information; underlying principle: phase relationship in capacitors (I leads V).

Q113. In an AC circuit containing an inductor, the current through an ideal inductor lags the inductor’s voltage by approximately:

Correct Answer: C
Explanation: For an ideal inductor, voltage leads current by 90°, so current lags voltage by 90°.
Citation: ASVAB content domain — Electronics Information; underlying principle: phase relationship in inductors (I lags V).

Q114. A transistor described as having “current gain” is primarily used because a small base current can control:

Correct Answer: B
Explanation: In a BJT, a small base current allows a much larger collector current, providing current amplification or switching control.
Citation: ASVAB content domain — Electronics Information; underlying principle: transistor current gain (base controls collector).

Q115. A digital logic gate outputs HIGH only when both inputs are HIGH. This is a(n):

Correct Answer: B
Explanation: An AND gate requires both inputs to be HIGH for the output to be HIGH.
Citation: ASVAB content domain — Electronics Information; underlying principle: basic logic gates (AND).

Q116. A digital XOR gate outputs HIGH when:

Correct Answer: B
Explanation: XOR is HIGH only when exactly one input is HIGH (inputs differ).
Citation: ASVAB content domain — Electronics Information; underlying principle: basic logic gates (XOR).

Q117. A voltage regulator in an electronic circuit is primarily used to:

Correct Answer: B
Explanation: Regulators control output voltage to stay near a set value even as input voltage or load current varies.
Citation: ASVAB content domain — Electronics Information; underlying principle: voltage regulation concept.

Q118. Two resistors, 6 Ω and 3 Ω, are connected in parallel across 12 V. What is the total current drawn (closest)?

Correct Answer: A
Explanation: Branch currents: I1 = 12/6 = 2.0 A and I2 = 12/3 = 4.0 A. Total is I_total = I1+I2 = 6.0 A.
Citation: ASVAB content domain — Electronics Information; underlying principle: parallel circuits (currents add).

Q119. Kirchhoff’s Voltage Law (KVL) states that around any closed loop in a circuit, the sum of voltage rises and drops equals:

Correct Answer: B
Explanation: KVL expresses conservation of energy: the algebraic sum of voltages around a closed loop is zero.
Citation: ASVAB content domain — Electronics Information; underlying principle: Kirchhoff’s Voltage Law (loop rule).

Q120. Kirchhoff’s Current Law (KCL) states that at a circuit node, the sum of currents entering equals:

Correct Answer: B
Explanation: KCL expresses conservation of charge: currents into a node equal currents out of the node.
Citation: ASVAB content domain — Electronics Information; underlying principle: Kirchhoff’s Current Law (node rule).

Q121. A 12.0 V battery has internal resistance 0.2 Ω. If it supplies 30 A, the terminal voltage under load is closest to:

Correct Answer: A
Explanation: Voltage drop inside the battery is I·r = 30×0.2 = 6.0 V. Terminal voltage ≈ 12.0 − 6.0 = 6.0 V.
Citation: ASVAB content domain — Electronics Information; underlying principle: internal resistance and voltage sag (V = E − Ir).

Q122. A circuit normally draws 2.5 A. Which fuse rating is the best match for basic protection without nuisance blowing?

Correct Answer: C
Explanation: A fuse should be rated just above normal operating current; 3 A provides margin over 2.5 A while still offering protection.
Citation: ASVAB content domain — Electronics Information; underlying principle: overcurrent protection (selecting fuse rating).

Q123. Two capacitors, 10 µF and 20 µF, are connected in series. The equivalent capacitance is closest to:

Correct Answer: A
Explanation: For capacitors in series: 1/C_eq = 1/C1 + 1/C2, so C_eq = (C1·C2)/(C1+C2) = (10·20)/(30) ≈ 6.7 µF.
Citation: ASVAB content domain — Electronics Information; underlying principle: series capacitance (reciprocal sum).

Q124. Capacitors 4.7 µF, 2.2 µF, and 1.0 µF are connected in parallel. The equivalent capacitance is closest to:

Correct Answer: A
Explanation: Capacitances in parallel add directly: C_eq = 4.7+2.2+1.0 = 7.9 µF.
Citation: ASVAB content domain — Electronics Information; underlying principle: parallel capacitance (direct sum).

Q125. A radio signal has frequency 100 MHz. Its wavelength in free space is closest to:

Correct Answer: A
Explanation: Wavelength λ = c/f. Using c ≈ 3×10⁸ m/s and f = 1×10⁸ Hz gives λ ≈ 3 m.
Citation: ASVAB content domain — Electronics Information; underlying principle: wave relationship (λ = c/f).

Q126. A resistor is labeled 2.6 kΩ ±5%. What resistance range is acceptable?

Correct Answer: A
Explanation: Tolerance is ±5%: ±0.05×2.6 kΩ = ±0.128 kΩ, giving 2.423 to 2.678 kΩ.
Citation: ASVAB content domain — Electronics Information; underlying principle: resistor tolerance (% of nominal).

Q127. A divider has 5 kΩ (top) and 6 kΩ (bottom) across 7.9 V. A 8 kΩ load is placed across the bottom resistor. The loaded output is closest to:

Correct Answer: A
Explanation: The load is in parallel with the bottom resistor, reducing the effective bottom resistance. Use R_bottom_eff = R_bottom||R_load, then V_out = V_in×R_bottom_eff/(R_top+R_bottom_eff).
Citation: ASVAB content domain — Electronics Information; underlying principle: loaded voltage divider (parallel loading effect).

Q128. To minimize measurement error when checking a circuit’s node voltage, a voltmeter should have:

Correct Answer: B
Explanation: A voltmeter is placed in parallel; high input resistance draws negligible current and avoids loading the circuit.
Citation: ASVAB content domain — Electronics Information; underlying principle: instrument loading (high voltmeter input resistance).

Q129. An RC circuit uses R = 11 kΩ and C = 0.37 µF. About how long is one time constant τ?

Correct Answer: A
Explanation: The time constant is τ = RC. After one τ, a charging capacitor reaches about 63% of its final value.
Citation: ASVAB content domain — Electronics Information; underlying principle: RC time constant (τ = RC).

Q130. An amplifier increases power from 2.5 W to 25.0 W. The power gain in decibels is closest to:

Correct Answer: A
Explanation: Power gain in dB is 10·log10(Pout/Pin).
Citation: ASVAB content domain — Electronics Information; underlying principle: decibel power ratio (10·log10(P2/P1)).

Q131. A 120 V AC load draws 5.0 A at power factor 0.70. Real power is closest to:

Correct Answer: A
Explanation: Real power is P = VI·pf; apparent power is S = VI.
Citation: ASVAB content domain — Electronics Information; underlying principle: real vs apparent power (P = VI·pf).

Q132. An LC circuit has L = 2.1 mH and C = 24 nF. The resonant frequency is closest to:

Correct Answer: A
Explanation: Use f0 = 1/(2π√(LC)).
Citation: ASVAB content domain — Electronics Information; underlying principle: LC resonance (f0 = 1/(2π√(LC))).

Q133. A standard silicon diode is reverse-biased well below its breakdown rating. Ideally, it will:

Correct Answer: B
Explanation: In reverse bias (below breakdown), a diode blocks current except for very small leakage.
Citation: ASVAB content domain — Electronics Information; underlying principle: diode reverse bias behavior (blocking current).

Q134. On most through-hole LEDs, the shorter lead typically indicates the:

Correct Answer: B
Explanation: Common convention: shorter lead is the cathode (negative), longer lead is the anode (positive).
Citation: ASVAB content domain — Electronics Information; underlying principle: component identification (LED polarity convention).

Q135. An op-amp configured with high gain and no negative feedback is most likely to operate as a:

Correct Answer: B
Explanation: Without negative feedback, small input differences drive the output to a rail, acting like a comparator.
Citation: ASVAB content domain — Electronics Information; underlying principle: op-amp open-loop gain and saturation.

Q136. A 13-bit ADC uses a 2.4 V reference. The ideal voltage per least significant bit (LSB) is closest to:

Correct Answer: A
Explanation: Ideal step size is approximately Vref/2^N.
Citation: ASVAB content domain — Electronics Information; underlying principle: ADC resolution (LSB ≈ Vref/2^N).

Q137. A pull-up resistor on a digital input pin is used primarily to:

Correct Answer: B
Explanation: A pull-up provides a defined HIGH state when undriven, preventing floating/noise-triggered states.
Citation: ASVAB content domain — Electronics Information; underlying principle: digital inputs (pull-up to prevent floating).

Q138. A 3.2 V PWM signal with duty cycle 58% drives a slow-responding load. The average (DC) voltage is closest to:

Correct Answer: A
Explanation: For a load that averages pulses, Vavg ≈ V_high×duty (assuming 0 V low).
Citation: ASVAB content domain — Electronics Information; underlying principle: PWM averaging (Vavg = V·duty).

Q139. In an ideal series RLC circuit at resonance, the total impedance is closest to:

Correct Answer: C
Explanation: At resonance, X_L and X_C cancel, leaving only resistance as the net impedance.
Citation: ASVAB content domain — Electronics Information; underlying principle: series resonance (X_L cancels X_C).

Q140. A common cause of hum in an audio system with multiple grounded devices is:

Correct Answer: B
Explanation: Multiple ground return paths allow small AC currents to circulate and inject hum into signal references.
Citation: ASVAB content domain — Electronics Information; underlying principle: ground loops and common-mode noise.

Q141. A resistor is labeled 7.8 kΩ ±10%. What resistance range is acceptable?

Correct Answer: A
Explanation: Tolerance is ±10%: ±0.10×7.8 kΩ = ±0.780 kΩ, giving 7.020 to 8.580 kΩ.
Citation: ASVAB content domain — Electronics Information; underlying principle: resistor tolerance (% of nominal).

Q142. A divider has 7 kΩ (top) and 9 kΩ (bottom) across 8.3 V. A 8 kΩ load is placed across the bottom resistor. The loaded output is closest to:

Q143. When measuring voltage across a component, the meter should have what internal characteristic to avoid loading?

Q144. An RC circuit uses R = 26 kΩ and C = 0.27 µF. About how long is one time constant τ?

Q145. An amplifier increases power from 2.0 W to 28.0 W. The power gain in decibels is closest to:

Correct Answer: A
Explanation: Power gain in dB is 10·log10(Pout/Pin).
Citation: ASVAB content domain — Electronics Information; underlying principle: decibel power ratio (10·log10(P2/P1)).

Q146. A 120 V AC load draws 5.0 A at power factor 0.82. Real power is closest to:

Q147. An LC circuit has L = 1.4 mH and C = 21 nF. The resonant frequency is closest to:

Correct Answer: A
Explanation: Use f0 = 1/(2π√(LC)).
Citation: ASVAB content domain — Electronics Information; underlying principle: LC resonance (f0 = 1/(2π√(LC))).

Q148. In normal reverse bias (not in breakdown), a silicon diode will mostly:

Q149. For a typical 5 mm LED, the shorter leg is usually the:

Q150. With no negative feedback, an op-amp will usually:

Q151. A 10-bit ADC uses a 2.2 V reference. The ideal voltage per least significant bit (LSB) is closest to:

Correct Answer: A
Explanation: Ideal step size is approximately Vref/2^N.
Citation: ASVAB content domain — Electronics Information; underlying principle: ADC resolution (LSB ≈ Vref/2^N).

Q152. Why would a designer add a pull-up resistor to a logic input?

Q153. A 3.7 V PWM signal with duty cycle 46% drives a slow-responding load. The average (DC) voltage is closest to:

Q154. At the resonant frequency of a series RLC circuit, the net impedance is approximately:

Q155. In audio systems, a persistent 60 Hz hum is often caused by:

Q156. A resistor is labeled 13.1 kΩ ±5%. What resistance range is acceptable?

Correct Answer: A
Explanation: Tolerance is ±5%: ±0.05×13.1 kΩ = ±0.653 kΩ, giving 12.398 to 13.703 kΩ.
Citation: ASVAB content domain — Electronics Information; underlying principle: resistor tolerance (% of nominal).

Q157. A divider has 9 kΩ (top) and 12 kΩ (bottom) across 8.7 V. A 8 kΩ load is placed across the bottom resistor. The loaded output is closest to:

Q158. A good voltmeter is designed to draw ______ from the circuit being tested.

Q159. An RC circuit uses R = 18 kΩ and C = 1.02 µF. About how long is one time constant τ?

Q160. An amplifier increases power from 1.5 W to 10.5 W. The power gain in decibels is closest to:

Correct Answer: A
Explanation: Power gain in dB is 10·log10(Pout/Pin).
Citation: ASVAB content domain — Electronics Information; underlying principle: decibel power ratio (10·log10(P2/P1)).

Q161. A 120 V AC load draws 5.0 A at power factor 0.94. Real power is closest to:

Q162. An LC circuit has L = 0.6 mH and C = 18 nF. The resonant frequency is closest to:

Correct Answer: A
Explanation: Use f0 = 1/(2π√(LC)).
Citation: ASVAB content domain — Electronics Information; underlying principle: LC resonance (f0 = 1/(2π√(LC))).

Q163. A diode operated in reverse bias below breakdown behaves most like a:

Q164. On a common LED package, lead length most often identifies the:

Q165. An op-amp used open-loop is commonly used as a:

Q166. A 13-bit ADC uses a 2.0 V reference. The ideal voltage per least significant bit (LSB) is closest to:

Correct Answer: A
Explanation: Ideal step size is approximately Vref/2^N.
Citation: ASVAB content domain — Electronics Information; underlying principle: ADC resolution (LSB ≈ Vref/2^N).

Q167. A pull-up resistor ensures a digital input reads what when nothing else drives it?

Q168. A 3.2 V PWM signal with duty cycle 34% drives a slow-responding load. The average (DC) voltage is closest to:

Q169. For a series RLC tuned to resonance, the circuit’s impedance is mainly set by:

Q170. Unwanted hum can appear when two devices share more than one ground path; this is called a:

Q171. A resistor is labeled 18.3 kΩ ±10%. What resistance range is acceptable?

Correct Answer: A
Explanation: Tolerance is ±10%: ±0.10×18.3 kΩ = ±1.830 kΩ, giving 16.470 to 20.130 kΩ.
Citation: ASVAB content domain — Electronics Information; underlying principle: resistor tolerance (% of nominal).

Q172. A divider has 11 kΩ (top) and 15 kΩ (bottom) across 9.1 V. A 8 kΩ load is placed across the bottom resistor. The loaded output is closest to:

Q173. If you want the voltage reading to be as accurate as possible, the voltmeter’s input resistance should be:

Q174. An RC circuit uses R = 10 kΩ and C = 0.92 µF. About how long is one time constant τ?

Q175. An amplifier increases power from 1.0 W to 11.0 W. The power gain in decibels is closest to:

Correct Answer: A
Explanation: Power gain in dB is 10·log10(Pout/Pin).
Citation: ASVAB content domain — Electronics Information; underlying principle: decibel power ratio (10·log10(P2/P1)).

Q176. A 120 V AC load draws 5.0 A at power factor 0.58. Real power is closest to:

Q177. An LC circuit has L = 4.3 mH and C = 15 nF. The resonant frequency is closest to:

Correct Answer: A
Explanation: Use f0 = 1/(2π√(LC)).
Citation: ASVAB content domain — Electronics Information; underlying principle: LC resonance (f0 = 1/(2π√(LC))).

Q178. Below reverse breakdown, the current through a reverse-biased diode is best described as:

Q179. In many standard LEDs, the shorter lead is connected to the:

Q180. If an op-amp has no feedback path, the output tends to:

Q181. A 10-bit ADC uses a 3.4 V reference. The ideal voltage per least significant bit (LSB) is closest to:

Correct Answer: A
Explanation: Ideal step size is approximately Vref/2^N.
Citation: ASVAB content domain — Electronics Information; underlying principle: ADC resolution (LSB ≈ Vref/2^N).

Q182. The main purpose of a pull-up on an input is to prevent:

Q183. A 3.7 V PWM signal with duty cycle 22% drives a slow-responding load. The average (DC) voltage is closest to:

Q184. In a series RLC circuit at resonance, the reactive parts effectively:

Q185. A ground-referenced signal may pick up hum if there is a:

Q186. A resistor is labeled 23.5 kΩ ±5%. What resistance range is acceptable?

Correct Answer: A
Explanation: Tolerance is ±5%: ±0.05×23.5 kΩ = ±1.177 kΩ, giving 22.372 to 24.727 kΩ.
Citation: ASVAB content domain — Electronics Information; underlying principle: resistor tolerance (% of nominal).

Q187. A divider has 13 kΩ (top) and 6 kΩ (bottom) across 9.5 V. A 8 kΩ load is placed across the bottom resistor. The loaded output is closest to:

Q188. To reduce disturbance of the circuit while measuring a voltage, the meter should have:

Q189. An RC circuit uses R = 25 kΩ and C = 0.82 µF. About how long is one time constant τ?

Q190. An amplifier increases power from 0.5 W to 7.5 W. The power gain in decibels is closest to:

Correct Answer: A
Explanation: Power gain in dB is 10·log10(Pout/Pin).
Citation: ASVAB content domain — Electronics Information; underlying principle: decibel power ratio (10·log10(P2/P1)).

Q191. A 120 V AC load draws 5.0 A at power factor 0.70. Real power is closest to: (Pick the best answer.)

Q192. An LC circuit has L = 3.6 mH and C = 12 nF. The resonant frequency is closest to:

Correct Answer: A
Explanation: Use f0 = 1/(2π√(LC)).
Citation: ASVAB content domain — Electronics Information; underlying principle: LC resonance (f0 = 1/(2π√(LC))).

Q193. With reverse polarity applied (within ratings), a diode primarily:

Q194. Lead length on many through-hole LEDs commonly marks the:

Q195. An op-amp without stabilizing feedback behaves most like a:

Q196. A 13-bit ADC uses a 3.2 V reference. The ideal voltage per least significant bit (LSB) is closest to:

Correct Answer: A
Explanation: Ideal step size is approximately Vref/2^N.
Citation: ASVAB content domain — Electronics Information; underlying principle: ADC resolution (LSB ≈ Vref/2^N).

Q197. A pull-up resistor is used to give an undriven input a:

Q198. A 3.2 V PWM signal with duty cycle 10% drives a slow-responding load. The average (DC) voltage is closest to:

Q199. When a series RLC circuit is at resonance, the impedance is dominated by:

Q200. Multiple chassis grounds tied together can create noise due to a:

Q201. A device draws 1.8 A from a 12 V source. Its effective resistance is closest to:

Correct Answer: A
Explanation: Use Ohm’s law: R = V/I. With V=12 V and I=1.8 A, R ≈ 6.67 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: Ohm’s law (R = V/I).

Q202. A 10 Ω resistor is connected across 15 V. Approximately how much power does it dissipate?

Correct Answer: A
Explanation: With voltage across a resistor, power is P = V²/R = 15.0²/10.0 ≈ 22.50 W.
Citation: ASVAB content domain — Electronics Information; underlying principle: power in resistors (P = V²/R).

Q203. Two resistors 12 Ω and 18 Ω are in parallel. Their equivalent resistance is closest to:

Correct Answer: A
Explanation: For two resistors in parallel: 1/Req = 1/R1 + 1/R2. Here Req ≈ 7.20 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: parallel resistance (reciprocal sum).

Q204. A 10 Ω resistor is in series with a parallel pair of 12 Ω and 6 Ω. The total resistance is closest to:

Correct Answer: A
Explanation: Combine the parallel pair first: R|| = (R1·R2)/(R1+R2) ≈ 4.00 Ω, then add the series resistor: R_total ≈ 14.00 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: series-parallel reduction (parallel then series).

Q205. An RC low-pass has R = 3.3 kΩ and C = 0.047 µF. The cutoff frequency is closest to:

Correct Answer: A
Explanation: Cutoff frequency is f_c = 1/(2πRC). Substituting values gives f_c ≈ 1026.1 Hz.
Citation: ASVAB content domain — Electronics Information; underlying principle: RC cutoff frequency (f_c = 1/(2πRC)).

Q206. A silicon diode is forward-biased and carries 0.1 A. Its forward voltage drop is typically closest to:

Correct Answer: A
Explanation: A conducting silicon diode is commonly approximated as about 0.7 V for quick estimates (actual drop varies with conditions).
Citation: ASVAB content domain — Electronics Information; underlying principle: silicon diode forward drop (≈0.7 V).

Q207. A full-wave bridge rectifier is connected to 60 Hz AC. The ripple frequency at the rectifier output is:

Correct Answer: A
Explanation: Full-wave rectification flips the negative half-cycle, doubling the pulse rate. Ripple frequency ≈ 2×input frequency.
Citation: ASVAB content domain — Electronics Information; underlying principle: full-wave rectification (ripple frequency doubles).

Q208. An ideal transformer has 500 primary turns and 50 secondary turns with 120 V on the primary. Secondary voltage is closest to:

Correct Answer: A
Explanation: For an ideal transformer, V_s/V_p = N_s/N_p, so V_s = 120×(50/500) ≈ 12.00 V.
Citation: ASVAB content domain — Electronics Information; underlying principle: ideal transformer voltage ratio (V ∝ turns).

Q209. An inductor of 20 mH carries 0.50 A. The stored energy is closest to:

Correct Answer: A
Explanation: E = ½LI². With L=0.020 H and I=0.50 A, E ≈ 0.002500 J = 2.50 mJ.
Citation: ASVAB content domain — Electronics Information; underlying principle: inductor energy (E = ½LI²).

Q210. At a fixed frequency, if capacitance is doubled, the capacitive reactance X_C will:

Correct Answer: A
Explanation: X_C = 1/(2πfC). Doubling C doubles the denominator, so X_C halves.
Citation: ASVAB content domain — Electronics Information; underlying principle: capacitive reactance dependence (X_C ∝ 1/C).

Q211. A resistor with color bands brown-black-red (ignore tolerance band) has a resistance of:

Correct Answer: A
Explanation: For 3-band resistors, the first two bands are digits and the third is the multiplier (10^n). Decode digits, then apply the multiplier.
Citation: ASVAB content domain — Electronics Information; underlying principle: resistor color code (digits + multiplier).

Q212. For an AND gate, the output is HIGH only when:

Correct Answer: A
Explanation: AND outputs HIGH only when all inputs are HIGH.
Citation: ASVAB content domain — Electronics Information; underlying principle: logic gate truth tables (AND).

Q213. The binary number 10110₂ equals what decimal value?

Correct Answer: A
Explanation: Sum powers of 2 where bits are 1. 10110₂ equals 22₁₀.
Citation: ASVAB content domain — Electronics Information; underlying principle: binary place value conversion.

Q214. An ideal inverting op-amp has R_in = 2 kΩ and R_f = 20 kΩ. The voltage gain (Vout/Vin) is closest to:

Correct Answer: A
Explanation: In an ideal inverting op-amp, A_v = -R_f/R_in = -20/2 ≈ -10.00.
Citation: ASVAB content domain — Electronics Information; underlying principle: inverting op-amp gain (A_v = -R_f/R_in).

Q215. A BJT used as a switch is considered ‘saturated’ when it is:

Correct Answer: A
Explanation: Saturation means the transistor is driven hard on; V_CE is small and it behaves like a closed switch.
Citation: ASVAB content domain — Electronics Information; underlying principle: BJT switching regions (saturation).

Q216. If a signal voltage increases by a factor of 10 (same impedance), the change in dB is closest to:

Correct Answer: A
Explanation: For equal impedances, voltage gain in dB is 20·log10(V2/V1). Apply the given voltage ratio.
Citation: ASVAB content domain — Electronics Information; underlying principle: decibel voltage ratio (20·log10(V2/V1)).

Q217. A square wave has frequency 2.5 kHz. Its period is closest to:

Correct Answer: A
Explanation: T = 1/f. For 2.5 kHz, T = 0.0004 s = 400 µs.
Citation: ASVAB content domain — Electronics Information; underlying principle: frequency–period relationship (T = 1/f).

Q218. A capacitor of 100 µF is charged to 12 V. The stored energy is closest to:

Correct Answer: A
Explanation: E = ½CV². With C=0.000100 F and V=12.0 V, E ≈ 0.007200 J = 7.20 mJ.
Citation: ASVAB content domain — Electronics Information; underlying principle: capacitor energy (E = ½CV²).

Q219. A 9 V source powers two red LEDs (assume 2.0 V each) in series with a resistor for 20 mA. The resistor value is closest to:

Correct Answer: A
Explanation: First find resistor voltage: V_R = V_s − n·V_f = 9.0 − 2×2.0 = 5.0 V. Then R = V_R/I ≈ 5.0/0.020 ≈ 250.0 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: LED current limiting (R = (V_s − ΣV_f)/I).

Q220. Which filter primarily passes low frequencies and attenuates high frequencies?

Correct Answer: A
Explanation: A low-pass passes frequencies below cutoff and attenuates higher frequencies.
Citation: ASVAB content domain — Electronics Information; underlying principle: filter types (low-pass behavior).

Q221. A circuit current is 0.75 A when connected to 9.0 V. The circuit resistance is closest to:

Correct Answer: A
Explanation: Use Ohm’s law: R = V/I. With V=9 V and I=0.75 A, R ≈ 12.00 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: Ohm’s law (R = V/I).

Q222. A 5.6 Ω load is connected across 12 V. Approximately how much power is delivered to the load?

Correct Answer: A
Explanation: With voltage across a resistor, power is P = V²/R = 12.0²/5.6 ≈ 25.71 W.
Citation: ASVAB content domain — Electronics Information; underlying principle: power in resistors (P = V²/R).

Q223. Resistors 30 Ω and 10 Ω are connected in parallel. The equivalent resistance is closest to:

Correct Answer: A
Explanation: For two resistors in parallel: 1/Req = 1/R1 + 1/R2. Here Req ≈ 7.50 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: parallel resistance (reciprocal sum).

Q224. A circuit has a 4 Ω resistor in series with a parallel pair of 8 Ω and 8 Ω. Total resistance is closest to:

Correct Answer: A
Explanation: Combine the parallel pair first: R|| = (R1·R2)/(R1+R2) ≈ 4.00 Ω, then add the series resistor: R_total ≈ 8.00 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: series-parallel reduction (parallel then series).

Q225. An RC filter uses R = 10 kΩ and C = 0.01 µF. The cutoff frequency is closest to:

Correct Answer: A
Explanation: Cutoff frequency is f_c = 1/(2πRC). Substituting values gives f_c ≈ 1591.5 Hz.
Citation: ASVAB content domain — Electronics Information; underlying principle: RC cutoff frequency (f_c = 1/(2πRC)).

Q226. In many circuits, a forward-biased silicon diode is approximated as having a voltage drop of about:

Q227. A full-wave rectifier uses a 50 Hz AC input. The main ripple frequency after rectification is:

Q228. An ideal transformer has 200 primary turns and 800 secondary turns. If 12 V is applied to the primary, the secondary voltage is closest to:

Correct Answer: A
Explanation: For an ideal transformer, V_s/V_p = N_s/N_p, so V_s = 12×(800/200) ≈ 48.00 V.
Citation: ASVAB content domain — Electronics Information; underlying principle: ideal transformer voltage ratio (V ∝ turns).

Q229. A 5 mH inductor carries 2.0 A. The energy stored in its magnetic field is closest to:

Correct Answer: A
Explanation: E = ½LI². With L=0.005 H and I=2.00 A, E ≈ 0.010000 J = 10.00 mJ.
Citation: ASVAB content domain — Electronics Information; underlying principle: inductor energy (E = ½LI²).

Q230. At a fixed frequency, if inductance is doubled, the inductive reactance X_L will:

Correct Answer: A
Explanation: X_L = 2πfL. Doubling L doubles X_L.
Citation: ASVAB content domain — Electronics Information; underlying principle: inductive reactance dependence (X_L ∝ L).

Q231. A resistor marked yellow-violet-orange (ignore tolerance) has a value of:

Q232. For an OR gate, the output is LOW only when:

Correct Answer: A
Explanation: OR outputs LOW only when all inputs are LOW.
Citation: ASVAB content domain — Electronics Information; underlying principle: logic gate truth tables (OR).

Q233. Convert 11001₂ to decimal.

Correct Answer: A
Explanation: Sum powers of 2 where bits are 1. 11001₂ equals 25₁₀.
Citation: ASVAB content domain — Electronics Information; underlying principle: binary place value conversion.

Q234. An ideal inverting amplifier uses R_in = 5 kΩ and R_f = 15 kΩ. Its gain is closest to:

Correct Answer: A
Explanation: In an ideal inverting op-amp, A_v = -R_f/R_in = -15/5 ≈ -3.00.
Citation: ASVAB content domain — Electronics Information; underlying principle: inverting op-amp gain (A_v = -R_f/R_in).

Q235. In BJT switching, saturation means the transistor is:

Correct Answer: A
Explanation: In saturation, extra base drive does not significantly increase collector current; the device is essentially ‘maxed out’ on.
Citation: ASVAB content domain — Electronics Information; underlying principle: BJT switching regions (saturation condition).

Q236. A voltage gain of 2 (same impedance) corresponds to approximately how many dB?

Q237. A clock runs at 8.0 MHz. Its period is closest to:

Correct Answer: A
Explanation: T = 1/f. At 8.0 MHz, T = 125 ns.
Citation: ASVAB content domain — Electronics Information; underlying principle: frequency–period relationship (T = 1/f).

Q238. A 10 µF capacitor is charged to 50 V. Stored energy is closest to:

Correct Answer: A
Explanation: E = ½CV². With C=0.000010 F and V=50.0 V, E ≈ 0.012500 J = 12.50 mJ.
Citation: ASVAB content domain — Electronics Information; underlying principle: capacitor energy (E = ½CV²).

Q239. A 12 V supply drives three LEDs (assume 2.1 V each) in series at 15 mA. Series resistor is closest to:

Correct Answer: A
Explanation: First find resistor voltage: V_R = V_s − n·V_f = 12.0 − 3×2.1 = 5.7 V. Then R = V_R/I ≈ 5.7/0.015 ≈ 380.0 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: LED current limiting (R = (V_s − ΣV_f)/I).

Q240. Which filter primarily passes high frequencies and attenuates low frequencies?

Correct Answer: A
Explanation: A high-pass attenuates low frequencies and passes higher frequencies.
Citation: ASVAB content domain — Electronics Information; underlying principle: filter types (high-pass behavior).

Q241. A 24 V supply pushes 3.0 A through a load. The load resistance is closest to:

Correct Answer: A
Explanation: Use Ohm’s law: R = V/I. With V=24 V and I=3 A, R ≈ 8.00 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: Ohm’s law (R = V/I).

Q242. A 33 Ω resistor has 9.0 V across it. Approximately how much power is dissipated?

Correct Answer: A
Explanation: With voltage across a resistor, power is P = V²/R = 9.0²/33.0 ≈ 2.45 W.
Citation: ASVAB content domain — Electronics Information; underlying principle: power in resistors (P = V²/R).

Q243. Two resistors 8 Ω and 24 Ω are placed in parallel. The equivalent resistance is closest to:

Correct Answer: A
Explanation: For two resistors in parallel: 1/Req = 1/R1 + 1/R2. Here Req ≈ 6.00 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: parallel resistance (reciprocal sum).

Q244. A 2 Ω resistor is in series with a parallel pair of 3 Ω and 6 Ω. Total resistance is closest to:

Correct Answer: A
Explanation: Combine the parallel pair first: R|| = (R1·R2)/(R1+R2) ≈ 2.00 Ω, then add the series resistor: R_total ≈ 4.00 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: series-parallel reduction (parallel then series).

Q245. An RC circuit has R = 2.2 kΩ and C = 0.1 µF. Its cutoff frequency is closest to:

Correct Answer: A
Explanation: Cutoff frequency is f_c = 1/(2πRC). Substituting values gives f_c ≈ 723.4 Hz.
Citation: ASVAB content domain — Electronics Information; underlying principle: RC cutoff frequency (f_c = 1/(2πRC)).

Q246. A standard silicon rectifier diode conducting normally is often modeled as dropping approximately:

Q247. With a full-wave rectifier on a 60 Hz line, the rectified waveform peaks occur at what frequency?

Q248. A transformer has a turns ratio of 10:1 (primary:secondary). If the primary is 240 V, the secondary is closest to:

Correct Answer: A
Explanation: For an ideal transformer, V_s/V_p = N_s/N_p, so V_s = 240×(1/10) ≈ 24.00 V.
Citation: ASVAB content domain — Electronics Information; underlying principle: ideal transformer voltage ratio (V ∝ turns).

Q249. An inductor of 40 mH carries 0.20 A. Stored energy is closest to:

Correct Answer: A
Explanation: E = ½LI². With L=0.040 H and I=0.20 A, E ≈ 0.000800 J = 0.80 mJ.
Citation: ASVAB content domain — Electronics Information; underlying principle: inductor energy (E = ½LI²).

Q250. At a fixed capacitance, if frequency is doubled, the capacitive reactance X_C will:

Correct Answer: A
Explanation: X_C = 1/(2πfC). Doubling f halves X_C.
Citation: ASVAB content domain — Electronics Information; underlying principle: capacitive reactance dependence (X_C ∝ 1/f).

Q251. A resistor with bands red-red-brown (ignore tolerance) is:

Q252. A NOT gate (inverter) outputs HIGH when the input is:

Correct Answer: A
Explanation: NOT inverts: input HIGH becomes LOW.
Citation: ASVAB content domain — Electronics Information; underlying principle: logic gate truth tables (NOT).

Q253. The binary value 100111₂ equals what in decimal?

Correct Answer: A
Explanation: Sum powers of 2 where bits are 1. 100111₂ equals 39₁₀.
Citation: ASVAB content domain — Electronics Information; underlying principle: binary place value conversion.

Q254. An inverting op-amp uses R_in = 1 kΩ and R_f = 47 kΩ. Gain is closest to:

Correct Answer: A
Explanation: In an ideal inverting op-amp, A_v = -R_f/R_in = -47/1 ≈ -47.00.
Citation: ASVAB content domain — Electronics Information; underlying principle: inverting op-amp gain (A_v = -R_f/R_in).

Q255. A BJT in cutoff is best described as:

Correct Answer: A
Explanation: Cutoff means base-emitter is not forward biased, so collector current is approximately zero.
Citation: ASVAB content domain — Electronics Information; underlying principle: BJT switching regions (cutoff).

Q256. If voltage is reduced to half (same impedance), the change is closest to:

Q257. A signal has frequency 400 Hz. Its period is closest to:

Correct Answer: A
Explanation: T = 1/f. For 400 Hz, T = 0.0025 s = 2.50 ms.
Citation: ASVAB content domain — Electronics Information; underlying principle: frequency–period relationship (T = 1/f).

Q258. A capacitor of 470 µF is charged to 5.0 V. Stored energy is closest to:

Correct Answer: A
Explanation: E = ½CV². With C=0.000470 F and V=5.0 V, E ≈ 0.005875 J = 5.88 mJ.
Citation: ASVAB content domain — Electronics Information; underlying principle: capacitor energy (E = ½CV²).

Q259. A 5 V supply drives one LED (assume 2.0 V) at 10 mA. The resistor is closest to:

Correct Answer: A
Explanation: First find resistor voltage: V_R = V_s − n·V_f = 5.0 − 1×2.0 = 3.0 V. Then R = V_R/I ≈ 3.0/0.010 ≈ 300.0 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: LED current limiting (R = (V_s − ΣV_f)/I).

Q260. A band-pass filter is designed to:

Correct Answer: A
Explanation: Band-pass filters pass a middle band and attenuate frequencies outside the band.
Citation: ASVAB content domain — Electronics Information; underlying principle: filter types (band-pass behavior).

Q261. A resistor has 6.0 V across it and 0.20 A through it. Its resistance is closest to:

Correct Answer: A
Explanation: Use Ohm’s law: R = V/I. With V=6 V and I=0.2 A, R ≈ 30.00 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: Ohm’s law (R = V/I).

Q262. A 4.7 Ω resistor is placed across 6.0 V. Approximately how much power is dissipated?

Correct Answer: A
Explanation: With voltage across a resistor, power is P = V²/R = 6.0²/4.7 ≈ 7.66 W.
Citation: ASVAB content domain — Electronics Information; underlying principle: power in resistors (P = V²/R).

Q263. Resistors 15 Ω and 60 Ω are in parallel. The equivalent resistance is closest to:

Correct Answer: A
Explanation: For two resistors in parallel: 1/Req = 1/R1 + 1/R2. Here Req ≈ 12.00 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: parallel resistance (reciprocal sum).

Q264. A 7 Ω resistor is in series with a parallel pair of 14 Ω and 28 Ω. Total resistance is closest to:

Correct Answer: A
Explanation: Combine the parallel pair first: R|| = (R1·R2)/(R1+R2) ≈ 9.33 Ω, then add the series resistor: R_total ≈ 16.33 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: series-parallel reduction (parallel then series).

Q265. A simple RC filter has R = 47 kΩ and C = 0.0022 µF. Cutoff frequency is closest to:

Correct Answer: A
Explanation: Cutoff frequency is f_c = 1/(2πRC). Substituting values gives f_c ≈ 1539.2 Hz.
Citation: ASVAB content domain — Electronics Information; underlying principle: RC cutoff frequency (f_c = 1/(2πRC)).

Q266. For quick estimates, the forward drop of a silicon PN junction diode is taken as about:

Q267. A bridge rectifier on a 50 Hz source produces pulsating DC at approximately:

Q268. An ideal transformer has 150 primary turns and 75 secondary turns with 18 V on the primary. Secondary voltage is closest to:

Correct Answer: A
Explanation: For an ideal transformer, V_s/V_p = N_s/N_p, so V_s = 18×(75/150) ≈ 9.00 V.
Citation: ASVAB content domain — Electronics Information; underlying principle: ideal transformer voltage ratio (V ∝ turns).

Q269. A 12 mH inductor carries 1.5 A. The energy stored is closest to:

Correct Answer: A
Explanation: E = ½LI². With L=0.012 H and I=1.50 A, E ≈ 0.013500 J = 13.50 mJ.
Citation: ASVAB content domain — Electronics Information; underlying principle: inductor energy (E = ½LI²).

Q270. At a fixed inductance, if frequency is doubled, the inductive reactance X_L will:

Correct Answer: A
Explanation: X_L = 2πfL. Doubling f doubles X_L.
Citation: ASVAB content domain — Electronics Information; underlying principle: inductive reactance dependence (X_L ∝ f).

Q271. A resistor with bands green-blue-brown (ignore tolerance) has a resistance of:

Q272. For a NAND gate, the output is LOW only when:

Correct Answer: A
Explanation: NAND is the inverse of AND, so it is LOW only when both inputs are HIGH.
Citation: ASVAB content domain — Electronics Information; underlying principle: logic gate truth tables (NAND).

Q273. Convert 111000₂ to decimal.

Correct Answer: A
Explanation: Sum powers of 2 where bits are 1. 111000₂ equals 56₁₀.
Citation: ASVAB content domain — Electronics Information; underlying principle: binary place value conversion.

Q274. An inverting op-amp has R_in = 10 kΩ and R_f = 100 kΩ. Gain is closest to:

Correct Answer: A
Explanation: In an ideal inverting op-amp, A_v = -R_f/R_in = -100/10 ≈ -10.00.
Citation: ASVAB content domain — Electronics Information; underlying principle: inverting op-amp gain (A_v = -R_f/R_in).

Q275. For a BJT switch, ‘cutoff’ means:

Correct Answer: A
Explanation: Cutoff corresponds to the transistor being off due to insufficient base-emitter forward bias.
Citation: ASVAB content domain — Electronics Information; underlying principle: BJT switching regions (cutoff condition).

Q276. A voltage gain of 5 (same impedance) is closest to how many dB?

Q277. A waveform repeats every 0.002 s. Its frequency is closest to:

Correct Answer: A
Explanation: f = 1/T. If T = 0.002 s, f = 500 Hz.
Citation: ASVAB content domain — Electronics Information; underlying principle: frequency–period relationship (f = 1/T).

Q278. A 1.0 µF capacitor is charged to 200 V. Stored energy is closest to:

Correct Answer: A
Explanation: E = ½CV². With C=0.000001 F and V=200.0 V, E ≈ 0.020000 J = 20.00 mJ.
Citation: ASVAB content domain — Electronics Information; underlying principle: capacitor energy (E = ½CV²).

Q279. A 24 V supply drives four LEDs (assume 3.0 V each) at 25 mA. The resistor is closest to:

Correct Answer: A
Explanation: First find resistor voltage: V_R = V_s − n·V_f = 24.0 − 4×3.0 = 12.0 V. Then R = V_R/I ≈ 12.0/0.025 ≈ 480.0 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: LED current limiting (R = (V_s − ΣV_f)/I).

Q280. A notch (band-stop) filter is designed to:

Correct Answer: A
Explanation: A notch filter attenuates a selected band while passing others.
Citation: ASVAB content domain — Electronics Information; underlying principle: filter types (band-stop/notch behavior).

Q281. A load draws 2.4 A from a 36 V source. The load resistance is closest to:

Correct Answer: A
Explanation: Use Ohm’s law: R = V/I. With V=36 V and I=2.4 A, R ≈ 15.00 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: Ohm’s law (R = V/I).

Q282. A 22 Ω resistor is connected across 48 V. Approximately how much power is dissipated?

Correct Answer: A
Explanation: With voltage across a resistor, power is P = V²/R = 48.0²/22.0 ≈ 104.73 W.
Citation: ASVAB content domain — Electronics Information; underlying principle: power in resistors (P = V²/R).

Q283. Two resistors 20 Ω and 5 Ω are in parallel. The equivalent resistance is closest to:

Correct Answer: A
Explanation: For two resistors in parallel: 1/Req = 1/R1 + 1/R2. Here Req ≈ 4.00 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: parallel resistance (reciprocal sum).

Q284. A 5 Ω resistor is in series with a parallel pair of 10 Ω and 20 Ω. Total resistance is closest to:

Correct Answer: A
Explanation: Combine the parallel pair first: R|| = (R1·R2)/(R1+R2) ≈ 6.67 Ω, then add the series resistor: R_total ≈ 11.67 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: series-parallel reduction (parallel then series).

Q285. An RC network has R = 1.0 kΩ and C = 0.22 µF. The cutoff frequency is closest to:

Q286. A silicon diode in forward conduction typically drops roughly:

Q287. A full-wave rectifier fed by 60 Hz produces a pulsating output at:

Q288. A transformer has a 1:4 turns ratio (primary:secondary). If the primary is 6 V, the secondary is closest to:

Correct Answer: A
Explanation: For an ideal transformer, V_s/V_p = N_s/N_p, so V_s = 6×(4/1) ≈ 24.00 V.
Citation: ASVAB content domain — Electronics Information; underlying principle: ideal transformer voltage ratio (V ∝ turns).

Q289. An inductor of 2.0 mH carries 3.0 A. Stored energy is closest to:

Correct Answer: A
Explanation: E = ½LI². With L=0.002 H and I=3.00 A, E ≈ 0.009000 J = 9.00 mJ.
Citation: ASVAB content domain — Electronics Information; underlying principle: inductor energy (E = ½LI²).

Q290. At a fixed frequency, if capacitance is halved, the capacitive reactance X_C will:

Correct Answer: A
Explanation: X_C = 1/(2πfC). Halving C halves the denominator, so X_C doubles.
Citation: ASVAB content domain — Electronics Information; underlying principle: capacitive reactance dependence (X_C ∝ 1/C).

Q291. A resistor with bands orange-orange-brown (ignore tolerance) is:

Q292. For an XOR gate, the output is HIGH when the inputs are:

Correct Answer: A
Explanation: XOR outputs HIGH when the inputs are different.
Citation: ASVAB content domain — Electronics Information; underlying principle: logic gate truth tables (XOR).

Q293. The binary number 010101₂ equals what decimal value?

Correct Answer: A
Explanation: Sum powers of 2 where bits are 1. 010101₂ equals 21₁₀.
Citation: ASVAB content domain — Electronics Information; underlying principle: binary place value conversion.

Q294. An inverting op-amp uses R_in = 3.3 kΩ and R_f = 33 kΩ. Gain is closest to:

Correct Answer: A
Explanation: In an ideal inverting op-amp, A_v = -R_f/R_in = -33/3.3 ≈ -10.00.
Citation: ASVAB content domain — Electronics Information; underlying principle: inverting op-amp gain (A_v = -R_f/R_in).

Q295. A BJT operating in saturation behaves most like a:

Correct Answer: A
Explanation: A saturated BJT behaves like a closed switch with a small collector-emitter voltage.
Citation: ASVAB content domain — Electronics Information; underlying principle: BJT as a switch (saturation ≈ closed switch).

Q296. If voltage increases by a factor of 3 (same impedance), the change is closest to:

Q297. A signal has a period of 20 µs. Its frequency is closest to:

Correct Answer: A
Explanation: f = 1/T. With T = 20 µs, f = 50,000 Hz = 50.0 kHz.
Citation: ASVAB content domain — Electronics Information; underlying principle: frequency–period relationship (f = 1/T).

Q298. A capacitor of 22 µF is charged to 24 V. Stored energy is closest to:

Correct Answer: A
Explanation: E = ½CV². With C=0.000022 F and V=24.0 V, E ≈ 0.006336 J = 6.34 mJ.
Citation: ASVAB content domain — Electronics Information; underlying principle: capacitor energy (E = ½CV²).

Q299. A 6 V source drives two LEDs (assume 1.8 V each) at 30 mA. The resistor is closest to:

Correct Answer: A
Explanation: First find resistor voltage: V_R = V_s − n·V_f = 6.0 − 2×1.8 = 2.4 V. Then R = V_R/I ≈ 2.4/0.030 ≈ 80.0 Ω.
Citation: ASVAB content domain — Electronics Information; underlying principle: LED current limiting (R = (V_s − ΣV_f)/I).

Q300. Compared to a low-pass, a high-pass filter mainly differs in that it:

Correct Answer: A
Explanation: A high-pass is defined by attenuating low frequencies more than high frequencies.
Citation: ASVAB content domain — Electronics Information; underlying principle: filter types (high-pass vs low-pass).

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