360 Alternating Current Theory

Question 1

Direct current flows in a circuit from the force of a voltage potential where the polarity remains constant.

Question 2

Direct current is also called _________?

Answer 2

Unidirectional current- it accomplishes work while only flowing in one direction.

Question 3

Alternating current flows in a circuit from the force of a voltage potential where the polarity regularly reverses.

Question 4

The change in polarity in alternating current also causes ________.

Answer 4

the current flow to change direction.

Question 5

Alternating current is also called?

Answer 5

Bidirectional current- it accomplishes work while first flowing in one direction and then the other.

Question 6

What is induction?

Answer 6

The process of producing electrical energy (voltage and current) by means of cutting magnetic lines of force.

Question 7

What is a sine wave?

Answer 7

Also called a sinusoidal waveform. An alternating current that has only one frequency.

Question 8

What produces a sine wave?

Answer 8

A sine wave can be generated by a wire loop rotating within a magnetic field.

Question 9

When does sine wave voltage change?

Answer 9

Sine wave voltage swings positive then negative as conductors of the loop pass alternating north and south magnetic poles.

Question 10

When the magnetic field consists of _______ poles, induced voltage switches polarity ________ per revolution.

Answer 10

two
once

Question 11

How many times will induced voltage switch polarity when the magnetic field consists of four poles?

Answer 11

The induced voltage will switch polarity twice per revolution.

Question 12

The number of AC cycles per second is referred to as _______.

Answer 12

frequency

Question 13

What is the formula for frequency?

Answer 13

f = 1/t

f = frequency in Hertz
t = time (period) in seconds

Question 14

What formula is used to calculate the period of a sine wave?

Answer 14

t = 1/f

Question 15

What is an alteration?

Answer 15

An alteration is a half cycle- when an AC sine wave goes from zero to maximum positive to zero or from zero to maximum negative to zero

Question 16

An alternation may also be called ________.

Answer 16

a pulse

Question 17

Define pulse

Answer 17

A controlled change in voltage (positive or negative) which conveys information to a circuit.

Question 18

Define duration.

Answer 18

The absolute value of the interval during which a specified waveform or feature exits or continues

Question 19

The time of each half-cycle is called _______.

Answer 19

its duration

Question 20

The peak value of an AC sine wave is called the ______ of an alteration.

Answer 20

amplitude

Question 21

The average voltage is _______ times the peak value of one alteration.

Answer 21

0.636

Question 22

______ value is the maximum voltage or current reached during one alternation.

Answer 22

peak