Noise from unplugged power supply :S

[Kawakaze]

I have a ccd camera that I put a peltier element into, and there is noise from the power supply, even when it isn't plugged in. Just plugging the jack in gives noise, I tried the bypassing thing with a capacitor with no effect. Plugging the PSU in gives no change. I tried moving the power supply around and this makes no difference plugged in or not, any ideas? If the noise is from the power to to camera from the usb port, why would it only appear when i put the jack in? I really am confused with this.

The case is plastic, and i just noticed that when you even touch the 0v pin of the socket for the jack with a metal object, the noise comes back.

 

[dlgoff]

It's probably 60/50 Hz noise from power lines, etc. Have you tried using shielded wire from the supply? Is there an Earth ground on the supply? I would think that the project should be in a metal box so as to shied your project as well as the wiring.

 

[Kawakaze]

You were right, I just wrapped the cable up in tin foil and the noise was almost gone. Shielded cables it is :)

Thanks so much for your help!

 

[Kawakaze]

I just did some more testing, the noise is much better but it is still too much. Is there anything else to be done? Thanks :)