I have been reading a guide about testing ac voltage and mains voltage. It says that common alternating current is 60Hz (in America anyway, 50Hz in UK) It then says to measure voltage at this frequency.
My voltmeter isn't very sophisticated; nor is my knowledge of electricity. My voltmeter measures ac and dc current but not frequency
I have read i a forum that multimeters, analogue or otherwise, are designed for measuring mains frequency AC @ 50 or 60hz. Does this sound about right? It does to me. I'm guessing Uk ones are optimized for 50Hz and American ones for 60Hz
In this tutorial : https://www.youtube.com/watch?v=foGhjGu-FUg
(only a minute long)
the guy tests mains' frequency with his 'mulitmeter' and gets 0.04KHz reading , though he does say it is not very accurate at low frequencies. He appears to be touching the probes of the metre to the screws of a plug that is in a multi plug gang but the plug itself appears to be completely separate and not wired to an appliance.
1) Is this possible/safe or his he using, for example, a grounding plug. I'm hoping he wouldn't post something so reckless if you do need a grounding plug
2)If it is a normal plug , would he have to modify it in anyway? Again he doesn't say the set up of the plug which I find slightly irresponsible but he knows more of the risks than me. I'm a bit confused as i used to teach basic physics including wiring a plug. we didn't connect the plug to an appliance; we had short pieces of cable with live/earth/neurtal wires and attached those to the plug and the cable/chord could be seen coming out of the plug. In the video the plug must surely be wired but with the wires cut
so they are under the cable grip so not showing as how couold he measure the voltage if the plug isnt wired?
3) Regarding the tutorial again, am i correct in saying the mains voltage can be measured even if the socket is switched off. I think I remember the potential difference exists in the socket whether it is on or off. So in theory could he have done his test with his unattached plug in a wall socket? Could he have done it with the plug switched on or off or both?
5) Question 4 may answer question 5: does the multi plug gang in the video need to be attached to a wall socket that is on or off?
Many thanks for our help