Waveforms with captionsPeriod refers to a length of time, and in the context of oscilloscopes and AC, the period of an AC waveform is the length of time taken to complete one cycle - from 0V to maximum positive value, back down to lowest negative value and back to 0V. This is one complete cycle, which is repeated as long as the circuit is closed.

The period of the waveform shown here is 30 ms.

The number of cycles per second is known as the frequency of AC:

Frequency = 1/period

The frequency of the signal shown here is 33.33 Hz (1/30).

Another example: Mains electricity in Ireland alternates with a frequency of 50Hz. - the period of this supply is 20 ms (1/50).

See also:

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