# what do a.c. and d.c. mean?

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#1
I am very confused, my teacher has never taught us this and it has come up in a past paper, what do they mean? I know they stand for alternating current and direct current but I don't know how I can tell whether a circuit is a.c. or d.c.???? Thanks
0
7 years ago
#2
Alternating Current and Direct Current
1
7 years ago
#3
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#4
(Original post by WeedCanKill)
Alternating Current and Direct Current
Ik but how can I tell which a circuit has?
0
7 years ago
#5
(Original post by kitale.k)
Ik but how can I tell which a circuit has?
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7 years ago
#6
I always got taught that AC has the live, neutral and earth, but DC just has positive and negative. Although it's been YEARS since I did electronics so if anyone can clarify please do.
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7 years ago
#7
AC has a frequency. The frequency is the number of cycles per second.
A cycle is the voltage going from positive v through 0v to negative v and back to positive.
A graph of this would produce a sine wave.
UK domestic electricity for example has a frequency of 50Hz - 50 cycles per second.

DC has no frequency. It stays at one voltage. A graph would be a straight line.
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