# ASVAB Electronics Practice Test 1

#### Which of the following is NOT a type of resistor?

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 the following is the correct definition of an electrical cell?

An electrical cell supplies electrical current. Examples include batteries and solar cells.

#### If a circuit has 8 volts of power and 4 ohms of resistance, what will the current equal?

Current is measured in amps. The formula to use here is: I = V/R I = 8/4 I = 2

#### What type of electrical circuit is depicted above?

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.

#### Three amps equals how many milliamps?

A milliamp is one thousandth of an amp. So every amp equals 1,000 milliamps: 3 x 1,000 = 3,000.

#### The resistor color code for 2 is

The band code for a resistor is as follows: ‣ Black is 0 ‣ Brown is 1 ‣ Red is 2 ‣ Orange is 3 ‣ Yellow is 4 ‣ Green is 5 ‣ Blue is 6 ‣ Violet is 7 ‣ Gray is 8 ‣ White is 9

#### Electrical power can be calculated with the following formula: P = I x V What does the letter I represent in this formula?

P represents power, which is measured in watts. I represents current, which is measured in amperes. V represents voltage which is measured in volts.

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

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

Electrical resistance is measured in ohms, and can be measured with an ohmmeter.

#### Which of the following is the most conductive element?

The most conductive material is Silver followed by Copper and Gold.

#### What is the voltage in a circuit with 10 amps of current and 6 ohms of resistance?

The formula to use here is: V = I x R V = 10 x 6 V = 60

#### Moderated by the voltage regulator, system voltage during regular car operation is around

Normally, the system voltage is around 14.5 volts. Car accessories increase the demand on the system (dropping the voltage) but this is compensated by the voltage regulator, which increases the alternator's output until the system voltage is back to approximately 15.

#### AM radio stations broadcast in which frequency range?

Frequencies are measured in kilohertz, megahertz, or gigahertz. AM radio stations broadcast in the 530-1,700 kHz range.

#### Which of the following is the SI unit representing one cycle per second?

The hertz, or Hz, is the SI unit of cycles per second and is a measurement of frequency. The Ohm is a measurement of resistance and the Ampere is a measurement of flow rate of electric charge.

#### What is the load in this basic circuit model?

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.

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

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

#### What type of switch is pictured above?

Pushing the button breaks the circuit. When you release the button it returns to its normally closed (on) position.

#### Which of the following statements are correct regarding a Voltmeter?

A voltmeter is used to measure the potential difference between two points. It is used in parallel with a circuit when measuring voltage. Ideally a voltmeter should have high resistance so that no current flows through it while measuring the potential difference between the two points.