AC/DC Chapter 4-6

A common inductor found in fluorescent light fixtures is a

Ballast

Inductance is measured in

Henrys

*The concept of a magnetic field being formed around a conductor when current flows through it is called:

electromagnetism

The resistance provided by an inductor in an AC circuit is called

Inductive reactance

The energy stored by a capacitor is called an

Electrostatic charge

Total series inductance formula

LT\= L1+L2+L3

A coil that opposes any change in current flow is called an

Inductor

Total parallel capacitance

CT\= C1+C2+C3

Affects a DC circuit only when the current is first turned on, turned off, or when there is a change in the load resistance

Inductance

One of the effects a capacitor has in a DC circuit is that it will

Charge to a voltage equal to the source voltage

The apparent resistance to ac by a capacitor is called

Capacitive resistance

Total parallel inductive resistance

XLT\=1/[(1/XL1)+(1/XL2)+(1/XL3)]

In a power supply that converts an ac input to generate a dc output, a capacitor is commonly used to

Filter the rectifiers pulsating dc output

Total series capacitive reactance formula

XCT\= XC1+XC2+XC3

Capacitance is measured in

Farads

A time delay relay that uses an RC timing circuit is called an

Solid state time delay relay

Which is not an example of an electromagnetic device

Resistor

In order for a firm voltage divider to operate properly, the load resistance value should be at least \_________ times greater than resistance value of the voltage divider bleeder resistor.

10

In a series-parallel circuit, components that are connected in parallel will display characteristics of a(n) \____________.

parallel circuit

What is the result when a branch of a parallel circuit has an open?

The rest of the circuit will operate but with a reduced total current.

A variable resistor is different from a fixed resistor because it \__________.

can be adjusted

A short circuit in the branch of a parallel circuit will ___________.

a. cause an excessive amount of current to flow

b. damage or destroy the power supply

c. cause a short circuit across the power supply

d. all of the above

e. none of the above

all of the above

Which of the following is not one of the seven general steps for solving a combination circuit.

a. calculate the equivalent resistance for all parallel sections.

b. calculate the total resistance of the circuit.

c. calculate the total current

d. calculate the RC time constant

calculate the RC time constant

Which of the following is not a step for troubleshooting a parallel circuit to find a short?

a. disconnect the power supply

b. look for visible signs of damage

c. connect an ohmmeter across the main line

d. all of the above

e. none of the above

none of the above

Which of the following is an application of a combination circuit?

a. commercial building's lights

b. electrical outlets controlled by a switch

c. ceiling fan control

d. all of the above

e. none of the above

all of the above

A circuit that uses resistors to produce a voltage that is lower than the source voltage is called a \__________.

voltage divider

A \__________ is an electrical device that converts AC electricity from one voltage level to another.

Transformer

A common application of mutual inductance is found in a device called a \__________.

Transformer

Which of the following is not a component of a transformer?

Plate

In order to calculate the output voltage of a transformer, divide the input voltage by the \__________.

Turns Ratio

Which of the following is a method to troubleshoot a transformer?

Measuring the continuity of the coils

Transformers are usually rated in units called \__________.

Volt Amperes

The power relationship on a transformer states that \__________.

Power in\= Power out + loss

The current load of a transformer is the current drawn by the \__________.

Primary winding itself

Which of the categories of transformers uses only one coil for the primary and secondary?

Autotransformer

Which type of transformer is commonly used to reduce line voltages of 240 VAC or 480 VAC to 120 VAC?

Control transformer

A common application of a center tap on the secondary of a transformer is a(n) \__________.

Distribution transformer