Continue to Site

Welcome to

Welcome to our site! is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Why interruption occurs in the phone when I touch a metal?

Not open for further replies.


Full Member level 2
Jul 14, 2005
Reaction score
Trophy points
Activity points
Why when I open my PC's case or any metallic part and touch it with my hand or with a screw driver I hear this low noise sound? Try it :)

I've posted this already in a previous post as a reply, but no one replied, I think it was agains the rules, so here is the question again!!

maybe no one knows the answer...even I, i just think that it has something to do with your body's conductivity,

Maybe its the humming sound produced in the transformer. Transformer always do that! Try to open a power supply and you can hear a low volume metallic sound. At this moment, I open my printer's power supply and it does produce a soft metallic sound. :)

Re: Why interruption occurs in the phone when I touch a meta

No NO!! You got me wrong neoaspilet11 :)
It happens when I'm speaking in the phone! :):)

Sounds like there is something wrong with your home's telephone system, it might be grounded improperly or there's a ground loop with the power system's earth ground.

Re: Why interruption occurs in the phone when I touch a meta

Hi Sceadwian,

Can you please explain it more?

I'm not a telco technician so I really can't explain more, I was just makeing a rough guess, you'd have to contact your local tele;phone company.

I think your PC is not grounded there for you have noise in your phone when touching it. it may be 50Hz (60Hz) noise.

Not open for further replies.

Part and Inventory Search

Welcome to