ASVAB Electronics Information Practice Test
Updated October 27, 2026
Electronics Information (EI) has 15 scored questions on the CAT-ASVAB. It covers electrical principles, circuits and common components. It doesn’t count toward your AFQT, but it’s part of the line scores for electronics, communications and other technical military jobs. Try the free questions below.
Key ideas
- Ohm’s law: voltage = current × resistance (V = I × R).
- Power: watts = voltage × current (P = V × I).
- Series circuits: one path for current; resistances add up, and an open anywhere stops all current.
- Parallel circuits: several paths; an open in one branch doesn’t stop the others.
- Units: voltage in volts, current in amperes (amps), resistance in ohms (Ω), power in watts.
Free Electronics Information practice questions
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A circuit has 12 volts and 4 ohms of resistance. How much current flows?Answer: AUsing Ohm's law, I = V ÷ R = 12 ÷ 4 = 3 amps.
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What unit is electrical resistance measured in?Answer: BResistance is measured in ohms (Ω). Voltage is in volts, current in amperes and power in watts.
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Three 10-ohm resistors are connected in series. What is the total resistance?Answer: DIn a series circuit, resistances add: 10 + 10 + 10 = 30 ohms.
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A light bulb uses 120 volts and draws 0.5 amps. How much power does it use?Answer: AP = V × I = 120 × 0.5 = 60 watts.
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In a home, lights in different rooms keep working when one bulb burns out. How are they wired?Answer: CIn a parallel circuit, each branch has its own path, so one burned-out bulb doesn't stop current to the others.
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Which device protects a circuit by breaking it when too much current flows?Answer: DFuses and circuit breakers open the circuit when current is too high, preventing overheating and fires.
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Which material is a good electrical conductor?Answer: ACopper conducts electricity well, which is why it's used in wiring. Rubber, glass and plastic are insulators.
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Two 10-ohm resistors are connected in parallel. What is the total resistance?Answer: AFor two equal resistors in parallel, total resistance is half of one: 10 ÷ 2 = 5 ohms.
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What unit measures electrical current?Answer: CCurrent is measured in amperes (amps). Voltage is in volts, resistance in ohms and power in watts.
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Which component stores electrical energy in an electric field?Answer: DA capacitor stores energy in an electric field between two plates. An inductor stores energy in a magnetic field.
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Household outlets in the United States supply about how many volts?Answer: CStandard U.S. household outlets supply about 120 volts AC. Larger appliances such as dryers use 240 volts.
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What kind of current does a car battery supply?Answer: ABatteries supply direct current, which flows in one direction. Household outlets supply alternating current.
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A diode allows current to flow:Answer: BA diode lets current flow in one direction and blocks it in the other, which is why diodes are used to convert AC to DC.
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A heater uses 10 amps at 120 volts. How much power does it draw?Answer: CPower = voltage × current = 120 × 10 = 1,200 watts.
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Which wire color is usually the ground wire in U.S. household wiring?Answer: CGround wires are usually green or bare copper. Black and red are usually hot wires, and white is usually neutral.
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What does a transformer do?Answer: DA transformer raises or lowers AC voltage using coils of wire. It doesn't work on steady DC.
See also General Science practice and Mechanical Comprehension.
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