4. Transformers

Question 1

changes the intensity of alternating voltage and current by mutual induction

Answer 1

Transformer

Question 2

is used to change the magnitude of voltage and current in an AC circuit

Answer 2

transformer

Question 3

a transformer with a turns ratio greater than 1 is a _____ transformer

Answer 3

step up

Question 4

a transformer with a turns ratio lesser than 1 is a ____transformer

Answer 4

step down

Question 5

increasing the turns, ______ the voltage but ______ the current

Answer 5

increases (v),

decreases (c)

Question 6

Voltage and turns are _____ proportional

Answer 6

directly

Question 7

Current and turns are _____ proportional

Answer 7

inversely

Question 8

Power =

Answer 8

Power = Voltage x Current

Question 9

THE THREE MAIN CAUSES OF TRANSFORMER INEFFICIENCY

Answer 9

• Resistance
• Hysteresis
• Eddy currents

Question 10

electric current in the copper wire experiences resistance that results in heat generation

Answer 10

Resistance (Copper Losses)

Question 11

the alternate reversal of the magnetic field caused by the alternating current causes and additional resistance (electricity induces magnetism)

Answer 11

Hysteresis

Question 12

these current oppose the magnetic field that induced them, creating a loss of transformer efficiency (magnetic field induces electricity)

Answer 12

Eddy Currents

Question 13

TYPES OF TRANSFORMER

Answer 13

• Closed-core transformer
• Autotransformer
• Shell-type transformer

Question 14

built about a square core of ferromagnetic material

Answer 14

Closed-core transformer

Question 15

consists of an iron core with only one winding of wire about it

Answer 15

Autotransformer

Question 16

based on self-induction rather than mutual induction

Answer 16

Autotransformer

Question 17

confines even more of the magnet field lines of the primary winding because the secondary is wrapped around it and there are essentially two close core

Answer 17

Shell-type transformer

Question 18

is a device that stores electrical energy in an electric field

Answer 18

Capacitor

Question 19

the relationship between the charge put on the body and its potential

Answer 19

Electrical Capacitance

Question 20

charge divided by potential

Answer 20

Capacitance (C = Q divide by V)

Question 21

SI unit of capacitance

Answer 21

Farad

Question 22

farads=

Answer 22

farads= coulombs/volts

Question 23

is to consider capacitance in terms of change of charge divided by the corresponding change in potential

Answer 23

Alternative definition of capacitance

Question 24

is the process of converting alternating voltage to direct voltage and therefor alternating current to direct current

Answer 24

Rectification

Question 25

inhibits flow of electrons

Answer 25

Resistor

Question 26

provides electric potential

Answer 26

Battery

Question 27

momentarily stores electric charge

Answer 27

Capacitor

Question 28

measures electric current

Answer 28

Ammeter

Question 29

measures electric potential

Answer 29

Voltmeter

Question 30

turns circuit on or off by providing infinite resistance

Answer 30

Switch

Question 31

increases or decreases voltage by fixed amount (AC only)

Answer 31

Transformer

Question 32

variable resistor

Answer 32

Rheostat

Question 33

allows electrons to flow in only one direction

Answer 33

Diode