electricity 2 Flashcards
(11 cards)
1
Q
what is alternating current?
A
current that constantly changes direction
2
Q
what is direct current?
A
current that goes in one direction only
3
Q
what is amplitude?
A
height of a wave
4
Q
in the UK what is the mains electricity (AC) and voltage?
A
electricity- 230v
frequency- 50Hz
5
Q
what does 50Hz (for example) tell us?
A
means there is 50 cycles per second, the current flow changes directions and back again 50 times
6
Q
how is electric energy delivered?
A
by cables in a giant network called the national grid
7
Q
what do step up transformers do? (3)
A
increase p.d
reduces current
reduces waste through heating
8
Q
what do step down transformers do? (3)
A
increases current
reduces p.d
safe supply voltage
9
Q
what is the red wire?
A
live
10
Q
what is the blue wire?
A
neutral
11
Q
what is the green wire?
A
earth
