Test and Measurement Forum

I finally found what is blowing up my MOSFETs: the PicoScope.

The PicoScope's power supply is placing 30 Vac onto the PicoScope's ground (!), which is connected to the circuit I am developing. Whenever I solder a MOSFET in place (with a grounded soldering iron), that's putting 30 V across the MOSFET, blowing it.

So: if you're using a PicoScope, make sure to ground your circuits directly to earth ground before you solder them!

Hi,
Firstly, the PicoScope PSU should not be putting out 30V AC in any way. If so please contact us on Help-Desk for a replacement:-
support@picotech.com
Secondly, I assume you are using a Laptop with an un-earthed PSU otherwise you will be grounded to mains earth anyway. It is always best policy to earth any circuit you are about to solder, it will be very sensitive to static damage if you don't.
Regards,
PeterF.