Computer Project - Grounding Question

[Eight]

Hi there,

I'm currently planning (and to an extent, building) a simple computer system based around a Z80 cpu.

Initially, I plan to power everything from standard batteries and when finished, I hope to make a simple case for it.

Most of the electronics side I know enough about but am a little lost on the question about grounding though.

If the circuit board and components all link to a central grounding point - should I be connecting this to a metal frame? Or for devices powered by DC batteries, is it enough just to put in a plastic case? I know that metal frames/chassis/cases (whatever) help with interference etc. but aside from that, should I do it?

I'm guessing things would be different if the device was connected to a mains power supply?

I'd really appreciate it if someone could help me out on this - or point me in the right direction. I've searched the web but found nothing that has really clarified things to me.

Thanks,

E

[hotwaterwizard]

I don't know but This guy might.

http://www.geocities.com/SiliconValley/Peaks/3938/

[surajbarkale]

You should not connect signal ground to the chassis for a mains connected equipment. There is a seperate Earthing lead in mains supply for it. Just design your PCB right & you won't have trouble of interferance unless you are in industrial envoryment.

[MP]

Eight,
It really depends upon what you will use the computer for. I use metal cases to protect against radio interference and I use the case as a ground to the battery system. This is also the industry standard for instrumentation.

Hope it is helpful.

MP