# a/c Mains frequency

Discussion in 'General Electronics Chat' started by pafrazier, Jun 25, 2012.

1. ### pafrazier Thread Starter Active Member

Jun 4, 2011
57
0
Hi,

If I were to read the frequency of a wall socket it would be 60 Hertz. Would it have a duty cycle of 50%?

Thanks

2. ### MrChips Moderator

Oct 2, 2009
12,646
3,458
Yes. The signal is supposed to be a pure sine wave. The picture of its frequency spectrum would be a delta-function at 60Hz. If the duty cycle was not 50% it would not be a pure sine wave.

3. ### pafrazier Thread Starter Active Member

Jun 4, 2011
57
0
Thanks for the info.

4. ### bretm Member

Feb 6, 2012
152
24
I don't know that the term "duty cycle" even applies here. 50% duty cycle means 50% on and 50% off. That's not what's happening with a sine wave.

5. ### Audioguru New Member

Dec 20, 2007
9,411
896
A pure sine wave has a 50% duty cycle because exactly 50% of it is positive and exactly 50% of it is negative. If its duty cycle was different then it would not be 50-50 and it would have even-numbered harmonics.