3.14 Resistive, Inductive And Capacitive Circuits

Question 1

Electrical circuits which contain capacitors and inductors are found to oppose?

Answer 1

Alternating current

Question 2

What are the two types of reactance?

Answer 2

-capacitive
-inductive

Question 3

In circuits with reactance, the AC voltage and AC current are found to be?

Answer 3

Out of phase with each other

Question 4

What are LCR circuits?

Answer 4

Circuits that contain inductors, capacitors, and resistors

Question 5

What is resistance sometimes called?

Answer 5

Real load

Question 6

Why is resistance sometimes called ‘real load’?

Answer 6

To distinguish it from the imaginary load of a circuits reactance

Question 7

What is reactive energy?

Answer 7

When energy is being pushed back and forth without being dissipated as heat by the inductor or doing any work

Question 8

The induced voltage across the coil is at maximum when?

Answer 8

The rate of change of current is at a maximum

Question 9

In a circuit with only inductive reactance how much does the current lag behind the voltage?

Answer 9

Quarter of a cycle or 90˚

Question 10

How can you increase the inductive reactance?

Answer 10

-introduce an iron core to the coil
-increase the frequency

Question 11

Does AC current flow through a capacitor?

Answer 11

No current flows through after thee initial pulse which charges the capacitor

Question 12

What is reactance?

Answer 12

Opposes the flow of alternating current

Question 13

What is reactive power?

Answer 13

The rate at which the reactive energy is transferred

Question 14

The true power of the AC varies constantly between?

Answer 14

Zero and its maximum value

Question 15

What are the units for true power?

Answer 15

Watt (W)

Question 16

What are the units for an inductive reactance and a capacitive circuit?

Answer 16

Ohms

Question 17

What is impedance in an AC circuit?

Answer 17

A combined measure of capacitive reactance and inductive reactance

Question 18

What is the skin effect?

Answer 18

Where a higher current is observed to flow along the outside ‘skin’ of a wire than in its core

Question 19

What causes the skin effect?

Answer 19

Eddy currents within the conducting wire itself

Question 20

Effective resistances are between what constant values?

Answer 20

0Hz to approximately 1,000Hz

Question 21

What is meant by impedance?

Answer 21

The measure of the opposition to AC in a circuit

Question 22

What does impedance take into account?

Answer 22

Resistance and reactance of the circuit

Question 23

What’s the difference between resistance and reactance?

Answer 23

Reactance still impedes current but no energy is dissipated

Question 27

What is ‘lost’ current of a capacitor?

Answer 27

The small amount of current that flows between the plates of the capacitor

Question 28

If a capacitor is said to have ‘lost’ current, what is the capacitor know as?

Answer 28

A capacitor with ‘loss’

Question 29

If the inductance reactance is higher than the capacitive reactance, the circuit is said to be?

Answer 29

Inductive

Question 30

If the capacitive reactance is higher than the inductive reactance, the circuit is said to be?

Answer 30

Mainly capacitive

Question 31

What causes a power factor les than 1?

Answer 31

When theres a presence of an inductive reactance in a device or circuit

Question 32

Real power is transferred to the?

Answer 32

Environment by the circuit or device

Question 33

Reactive power is?

Answer 33

Stored and returned to the circuit later in the AC cycle

Question 34

How are AC generators and transformers rated?

Answer 34

By their apparent power

Question 35

What are the units for the power of AC generators and transformers?

Answer 35

Volt-ampere (VA)