Hi all,
I expect questions like this have been asked lots, so sorry if its old ground!
I have made a RFID reader using a pic and some op amps, while developing on the bread board I had my scope connected most of the time.
Some of you can see this coming, when I disconnect the earth clip if the scope the circuit doesn't work as well as it should, if I touch the metal case of my PSU, it works, if I connect to a battery it only performs as I hoped if I touch the earth/ground line with my finger?
I have 100nF decoupling caps on each ic, two on the pic as it has two power inputs.
Do folks think a PCB with a good ground plane will get rid of the problem? Should I use different value decoupling caps? As its going to be hand held I could just have a earth on the handle but this seems a bit hap hazard!
Cheers Geoff
I expect questions like this have been asked lots, so sorry if its old ground!
I have made a RFID reader using a pic and some op amps, while developing on the bread board I had my scope connected most of the time.
Some of you can see this coming, when I disconnect the earth clip if the scope the circuit doesn't work as well as it should, if I touch the metal case of my PSU, it works, if I connect to a battery it only performs as I hoped if I touch the earth/ground line with my finger?
I have 100nF decoupling caps on each ic, two on the pic as it has two power inputs.
Do folks think a PCB with a good ground plane will get rid of the problem? Should I use different value decoupling caps? As its going to be hand held I could just have a earth on the handle but this seems a bit hap hazard!
Cheers Geoff