AC/DC Chapter 4-6

Which of the following is not an example of an electromagnetic device?

Resistor

The formula for calculating total parallel capacitance is

• CT = C1 + C2 + C3.

Which of the following is the correct formula for calculating total series inductance?

LT = L1 + L2 + L3.

A common inductor found in fluorescent light fixtures is a

Ballast

The apparent resistance to AC by a capacitor is called

* Capacitive reactance

A coil that opposes any change in current flow is called a(n)

Inductor

Which of the following is the correct formula for calculating total parallel inductive reactance in a parallel circuit?

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

The energy stored by a capacitor is called a(n)

Electrostatic charge

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

Capacitance is measured in

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

Inductive reactance

Capacitance is measured in

Farads

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

Charge to a voltage equal to the source voltage

A time-delay relay that uses an RC timing circuit is called a(n)

Solid-state, time-delay relay

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

Filter the rectifier's pulsating DC output

Inductance is measured in

Henrys

Which of the following is the total series capacitive reactance formula?

XCT = XC1 + XC2 + XC3.

Which of the following is a type of capacitor?

Electrolytic



Nonpolarized



Variable

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

* Electromagnetism

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

Voltage divider

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

Parallel circuit

In order to identify the series and parallel sections of a combination circuit,

Trace the current path

In order for a firm voltage divider to operate properly, the load resistance value should be at least the voltage divider bleeder resistor.

10

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

Calculate the RC time constant.

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

Disconnect the power supply.



O Look for visible signs of damage.



Connect an ohmmeter across the main ine



O All of the above



© None of the above

Which of the following is an application of a variable resistor?

Radio volume controls



O Television controls



O Dim lighting

A short circuit in the branch of a parallel circuit will

Cause an excessive amount of current to flow



Damage or destroy the power supply



Cause a short circuit across the power supply

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

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

Commercial building's lights



Electrical outlets controlled by a switch



Ceiling fan control

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

Plate

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

Distribution transformer

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

Transformer

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

Tums ratio

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

Control transformer

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

Measuring the continuity of the coils

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

Autotransformer