IEM

Question 1

a device that is used to change the magnitude of electric current and potential into higher and lower values.

Answer 1

Transformer

Question 2

Transformer applies the principle of

Answer 2

mutual induction

Question 3

Transformer will operate only with a

Answer 3

changing electric current (AC)

Question 4

Usually composed of wires wrapped around in an iron core and consists of

Answer 4

primary and secondary coils

Question 5

The change in the voltage is ______ to the ratio of the number of turns (windings) in the secondary coil (Ns) to the number of turns in the primary coil (Np).

Answer 5

directly proportional (tranformer law)

Question 6

The change in current across a transformer is in the ______ from the voltage change but in the ______.

Answer 6

opposite direction

same proportion

Question 7

transformer with a turns ratio greater than 1

Answer 7

Step up transformer

Question 8

Increases the voltage but decreases the current.

Answer 8

Step up tranformer

Question 9

a transformer with turns ratio less than 1

Answer 9

Step down transformer

Question 10

Decreases the voltage but increases the current.

Answer 10

Step down transformer

Question 11

is made from a single primary winding wrapped around a laminated magnetic core, and operates on the principle of self-induction.

Answer 11

Autotransformer

Question 12

tapped at various points along its length to provide a percentage of the primary voltage supply across its secondary load.

Answer 12

Single winding

Question 13

is a device that stores electric charges producing a potential difference (static voltage) across its plates, much like a small rechargeable battery.

Answer 13

Capacitor

Question 14

consists of two or more parallel conductive (metal) plates that are electrically separated either by air or insulating material.

Answer 14

Capacitor

Question 15

The insulating material between plates is called

Answer 15

dielectric

Question 16

is an electrical device which converts an alternating current (AC) into a direct current (DC) by allowing the current to flow through it in only one direction.

Answer 16

Rectifier

Question 17

the process of converting AC to DC.

Answer 17

Rectification

Question 18

a pulsating DC and not a smooth DC.

Answer 18

Output DC

Question 19

a pulsating DC and not a smooth DC.

Answer 19

Diodes

Question 20

Types of Rectification

Answer 20

1. Half-wave rectification
2. Full-wave rectification

Question 21

Uses one or two diodes that allow only half of the AC cycle to pass, while the other half is blocked.

Answer 21

Half wave rectification

Question 22

Uses several diodes that allow both the positive and negative cycle of the AC wave to pass.

Answer 22

Full wave rectification

Question 23

an electrical instrument that is used to control current by varying the resistance.

Answer 23

Rheostat

Question 24

able to vary the resistance in a circuit without interruption.

Answer 24

Rheostats

Question 25

a device that opens a circuit as soon as current climbs to unsafe levels.

Answer 25

Circuit breaker

Question 26

consists of a simple switch, connected to electromagnet.

Answer 26

The basic circuit breaker

Question 27

a backup pathway that provides an alternate route for electrical current to flow back into ground in the case of a problem in the wiring system.

Answer 27

Grounding system