Sheilding Question

Hi,
i would like to know at what potential do we keep the metal sheilding of a transmitter. Do we connect the metal sheilding to the ground of the circuit that lies inside or do we keep them electrically isolated.

Thanks.

Vaibhav Birit said:

i would like to know at what potential do we keep the metal sheilding of a transmitter. Do we connect the metal sheilding to the ground of the circuit that lies inside or do we keep them electrically isolated.

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You normally connect it to the ground of the circuit.

There is quite a bit of information written by/for radio amateurs on grounding and it does address shielding. Several things that I remember about grounding - one was only ground one end of the shield. I don't know quite why but my guess is to prevent it from becoming a conductor of significant amounts of current. Another recommendation by the experts is to ground everything to a single point and to bond the equipment ground to the electrical system ground with appropriately heavy wire. Again, lots of information exists, as I recall, in amateur radio publications and journals.

I'd bet that single ground connection on the sheild prevents the sheild from working like an antenna and coulping that noise into your ground. With 2 connections any potential induced in the sheild would appear on your ground.