I was trying to get rid of the humming noise coming from my speakers in my hi-fi system. It is an old piece of equipment from back when the UK appliances did not come with the mains plug and you had to add it yourself.
I noticed that the amplifier was not grounded so I added a cable from the chasis to the ground pin in the plug and violá: no more humming. I did test the continuity between the 3 pins in the plug using a multimeter, and also tested between live and the chasis of the amp and everything was nice and dandy.
I then connected (via rca) my CD player and I got hum again... so effectively, after checking the plug I found no ground in this one either, so I repeated the same procedure.
When testing, I found that between live and neutral in the plug, there was a little bit of continuity! So I checked my work, as I assumed, I messed up and accidentally made a contact between live and neutral somewhere... however, this contact was nowhere to be found.
Maybe there is something wrong with the cable I used for ground? I thought. So I unplugged it and put the device back to how it was earlier. But this small continuity was still present.
When measured in terms of resistance, it gave me a value of around 22 KOhm.
Is this normal at all? I am afraid of plugging the device to mains now!
I’m new to electronics and electrical theory, I just know very little from high school and I just finished my first semester of electrical engineering at university.