# Problem with Electrical Circuit Question

#### thecarefulone

Joined Mar 14, 2021
4
Hi! I have a question related to electronics:

Someone told you that there might be a problem with the electrical circuit: In addition to the standard 50Hz alternative voltage, it mights exist another disruptive frequency at 50.5Hz.

For how long, at least, should you measure the voltage in the outlet to know if this disruptive frequency actually exists or if it is a fake information ?

The answer is 2 seconds, but I can't understand why. Can someone explain? Thanks in advance.

#### ericgibbs

Joined Jan 29, 2010
18,666
hi one,
Welcome to AAC.
Consider if you had a frequency counter that had a display resolution of 1 cycle, how long would you have to wait for a full cycle.?

E

#### thecarefulone

Joined Mar 14, 2021
4
hi one,
Welcome to AAC.
Consider if you had a frequency counter that had a display resolution of 1 cycle, how long would you have to wait for a full cycle.?

E
It's period?

#### ericgibbs

Joined Jan 29, 2010
18,666
hi,
So what is the Period of a 50.5Hz or a 50Hz sine wave.?

E

#### thecarefulone

Joined Mar 14, 2021
4
hi,
So what is the Period of a 50.5Hz or a 50Hz sine wave.?

E
1/(50.5-50)= 2 seconds, it is like this?

#### ericgibbs

Joined Jan 29, 2010
18,666
hi one,
Can you post more details of the question, where did you find it.?
E

#### thecarefulone

Joined Mar 14, 2021
4
hi one,
Can you post more details of the question, where did you find it.?
E
It's from training quiz that my teacher put. It's exactly what I wrote on post, no more information is given.

#### ericgibbs

Joined Jan 29, 2010
18,666
hi,
OK,
Consider you had a frequency counter display that shows '000' Hz [ no decimal parts] how would you display 50.5Hz.?

As it is Homework I can only give you hints.
E

#### best peter

Joined Oct 9, 2011
6
Are the 2 frequencies at the outlet co-existing at the same time?
What instrument(s) is being used to measure the signals?

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