ASVAB Electronics Information Test — Questions and Answers

Question 1: What is the unit of electrical capacitance?

Henry
Farad (Correct answer)
Ohm
Siemens

Correct answer: Farad

Capacitance is measured in farads (F), named after Michael Faraday.

Question 2: In a parallel circuit with three 6-ohm resistors, what is the total resistance?

18 ohms
6 ohms
2 ohms (Correct answer)
3 ohms

Correct answer: 2 ohms

In parallel, total resistance = 1/(1/6+1/6+1/6) = 6/3 = 2 ohms.

Question 3: What does a diode primarily do in a circuit?

Amplifies current
Allows current to flow in only one direction (Correct answer)
Stores electrical energy
Measures voltage

Correct answer: Allows current to flow in only one direction

A diode is a semiconductor device that permits current to flow in one direction only.

Question 4: Which type of transformer steps voltage up from primary to secondary coil?

Step-down transformer
Isolation transformer
Step-up transformer (Correct answer)
Auto-transformer

Correct answer: Step-up transformer

A step-up transformer has more turns on the secondary coil than the primary, increasing voltage.

Question 5: What is the color code for a resistor with bands: Red, Red, Brown, Gold?

220 ohms ±5% (Correct answer)
2200 ohms ±5%
22 ohms ±5%
220 ohms ±10%

Correct answer: 220 ohms ±5%

Red=2, Red=2, Brown=×10 multiplier, Gold=±5% tolerance gives 220 ohms ±5%.

Question 6: What happens to capacitive reactance as frequency increases?

It increases
It remains constant
It decreases (Correct answer)
It doubles

Correct answer: It decreases

Capacitive reactance Xc = 1/(2πfC), so it decreases as frequency increases.

Question 7: Which semiconductor device can function as both a switch and an amplifier?

Capacitor
Resistor
Transistor (Correct answer)
Inductor

Correct answer: Transistor

A transistor can amplify signals or act as an electronic switch depending on how it is biased.

Question 8: What is the primary purpose of a fuse in an electrical circuit?

Increase current flow
Regulate voltage
Protect against overcurrent (Correct answer)
Store energy

Correct answer: Protect against overcurrent

A fuse melts and opens the circuit when current exceeds a safe level, protecting components.

Question 9: If a circuit has 12V across a 4-ohm resistor, how much power is dissipated?

3 watts
48 watts
36 watts (Correct answer)
8 watts

Correct answer: 36 watts

P = V²/R = 12²/4 = 144/4 = 36 watts.

Question 10: What does the term 'frequency' refer to in AC circuits?

The peak voltage value
The number of complete cycles per second (Correct answer)
The time for one cycle
The phase difference between voltage and current

Correct answer: The number of complete cycles per second

Frequency is measured in hertz (Hz) and indicates how many complete cycles occur each second.

Question 11: What type of circuit has only one path for current to flow?

Parallel circuit
Bridge circuit
Series circuit (Correct answer)
Complex circuit

Correct answer: Series circuit

In a series circuit, all components share the same single current path.

Question 12: What is the function of an inductor in an AC circuit?

Blocks DC and passes AC
Opposes changes in current (Correct answer)
Converts AC to DC
Amplifies voltage

Correct answer: Opposes changes in current

An inductor opposes changes in current due to its self-induced back-EMF (inductive reactance).

Question 13: Which material is considered a semiconductor?

Copper
Silicon (Correct answer)
Rubber
Silver

Correct answer: Silicon

Silicon is a classic semiconductor used in transistors, diodes, and integrated circuits.

Question 14: In electrical wiring, what does AWG stand for?

Alternating Wire Gauge
American Wire Gauge (Correct answer)
Ampere Wire Grade
Applied Wiring Guide

Correct answer: American Wire Gauge

AWG stands for American Wire Gauge, a standardized system for wire diameter sizes.

Question 15: What is the relationship between inductive reactance and frequency?

Inversely proportional
Not related
Directly proportional (Correct answer)
Exponentially proportional

Correct answer: Directly proportional

Inductive reactance XL = 2πfL, so it increases proportionally as frequency increases.

Question 16: What is the function of a rectifier in a power supply?

Converts DC to AC
Filters noise from signals
Converts AC to DC (Correct answer)
Regulates output voltage

Correct answer: Converts AC to DC

A rectifier uses diodes to convert alternating current (AC) into direct current (DC).

Question 17: When two capacitors are connected in series, the total capacitance is:

Greater than either capacitor
Equal to the sum of both
Less than the smallest capacitor (Correct answer)
Equal to the largest capacitor

Correct answer: Less than the smallest capacitor

Series capacitors combine like parallel resistors: 1/Ct = 1/C1 + 1/C2, yielding a smaller total.

Question 18: What is the purpose of a voltage regulator IC in a circuit?

Convert AC to DC
Maintain a stable output voltage despite input variations (Correct answer)
Amplify weak signals
Filter high-frequency noise

Correct answer: Maintain a stable output voltage despite input variations

A voltage regulator IC keeps the output voltage constant regardless of load or input fluctuations.

Question 19: What type of logic gate outputs HIGH only when all inputs are HIGH?

OR gate
NAND gate
NOR gate
AND gate (Correct answer)

Correct answer: AND gate

An AND gate produces a HIGH output only when every input is HIGH; otherwise, output is LOW.

Question 20: A circuit draws 3 amperes from a 9-volt battery. What is the circuit's resistance?

27 ohms
6 ohms
3 ohms (Correct answer)
0.33 ohms

Correct answer: 3 ohms

Using Ohm's Law: R = V/I = 9/3 = 3 ohms.

Question 21: What is the purpose of a bypass capacitor placed near an IC power pin?

Increase supply voltage
Filter high-frequency noise on the power supply line (Correct answer)
Store energy for backup power
Block DC current from the IC

Correct answer: Filter high-frequency noise on the power supply line

A bypass (decoupling) capacitor filters high-frequency noise and voltage spikes from the power supply.

ASVAB Electronics Information Test

What is the unit of electrical capacitance?

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