Electrical Circuits Flashcards Preview

Physics LV > Electrical Circuits > Flashcards

Flashcards in Electrical Circuits Deck (20):
1

What is an electric current

An electric current is s flow of electric charge

2

What do cells and batteries supply

Cells and batteries supply direct current (DC)

3

What is Direct current (D.C)

Current that always passes in the same direction

4

What is alternating current (A.C)

Current that is constantly changing direction

5

What type of supply is mains electricity

Alternating current (A.C)
In the UK it has a frequency of 50 cycles per second (50Hz) and is about 230V

6

What can a diode be used for

A diode may be used for half wave rectification of a.c

7

Most electrical appliances are connected to the mains using.........

A cable and a three pin plug

8

What are the colours of the different wires

Neutral wire = bLue (goes Left)
Live wire= bRown (goes Right)
Earth wire = green and yellow sTripes (goes to the Top

9

What is the case made of and why

The case is made of tough plastic or rubber, because these materials are good electrical insulators

10

What are the three pins made from and why

The three puns are made from brass, which is a good conductor of electricity

11

What happens if an electrical fault causes too great a current to flow

If an electrical fault causes to great a current to flow, the circuit is disconnected by a fuse or a circuit breaker in the live wire

12

What happens when the current in a fuse wire exceeds the rating of the fuse

It will melt, breaking the circuit

13

The thicker the wire in the fuse, ............

The higher the fuse's rating .
This us because the thinner wire cannot take such a big load as the thicker one can; the thinner one will just melt at the same voltage and current that the thicker one would be able to take

14

What are some circuits protected by

Residual current circuit breakers (RCCBs)

15

Which is faster, a fuse or RCCBs

RCCBs operate much faster than a fuse

16

How do RCCBs operate

RCCBs operate by detecting a difference in the current between the live wire and the neutral wires

17

Appliances with metal cases are usually .......

Earthed

18

In what case would there be no need for an earth wire connection

If the appliances are double insulated

19

The ................ And the .......... Together protect the wiring of a circuit

The earth wire and fuse together protect the wiring of a circuit

20

What substances can electrical charges move easily through

Metals