ASVAB Electronics

P = I × V

What does the letter I represent in this formula?

• watts

• voltage

• current

• impedance

Answer explanation

The correct answer is (C). The letter P represents power, which is measured in watts. The letter I represents current, which is measured in amperes. The letter V represents voltage which is measured in volts.

What is the load in this basic circuit model?

• A

• B

• C

• D

Answer explanation

The correct answer is (C). In a basic circuit model, there is a voltage source (pictured here as a battery at points A and B), a load, and conductors. The conductors are drawn using the lines and arrows. The load in this model is the light bulb pictured at point C. Examples of loads are light bulbs, resistors and motors.

Three amps equals how many milliamps?

• 0.003

• 30

• 300

• 3,000

Answer explanation

The correct answer is (D). A milliamp is one thousandth of an amp. So every amp equals 1,000 milliamps:
3 × 1,000 = 3,000

What type of electrical circuit is depicted below?

• A

• B

• C

• D

Answer explanation

The correct answer is (D). A series-parallel circuit has some loads wired in series and some loads wired in parallel. The loads in this circuit are R1, R2, and R3. R1 is wired in series while R2 and R3 are wired in parallel.

What device would you use to measure electrical resistance in a circuit.

• ohmmeter

• voltmeter

• ammeter

• electricity meter

Answer explanation

The correct answer is (A). Electrical resistance is measured in ohms, and can be measured with an ohmmeter.

Which of the following is NOT a type of resistor?

• potentiometer

• dielectric

• rheostat

• variable

Answer explanation

The correct answer is (B). A potentiometer is a three terminal resistor with a sliding contact. A rheostat is a two terminal variable resistor. A variable resistor is any resistor that allows you to change the amount of resistance. Potentiometers and rheostats are both types of variable resistors.

Which of these electrical devices can be used to store an electric charge?

• Semiconductor

• Diode

• Capacitor

• Transistor

Answer explanation

Capacitors consist of one or more pairs of metal conducting plates that are separated by an insulator. The insulator is called the dielectric. An electric charge builds up when a voltage is applied across the plates, which creates an electric field.

What does this symbol refer to?

• piezo transducer

• relay switch

• zener diode

• oscilloscope

Answer explanation

The correct answer is (A). A transducer is any device used to convert energy from one form to another. Piezo transducers are often used in microphones where they convert sound pressure to electrical voltage.

The amount of energy used by a consumer in their home or business is typically measured in

• current

• amps

• voltage

• kilowatt-hours

Answer explanation

The correct answer is (D). A kilowatt-hour (kWh) is a unit of energy equivalent to one kilowatt (1 kW) of power expended for one hour

AM radio stations broadcast in which frequency range?

• 530–1,700 kHz

• 7–1,002 MHz

• 1–40 GHz

• 60–1,000 AHz

Answer explanation

The correct answer is (A). Frequencies are measured in kilohertz, megahertz, or gigahertz. AM radio stations broadcast in the 530–1,700 kHz range.