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Electronics => Beginners => Topic started by: Aisalord on September 30, 2020, 12:55:24 pm

Title: old philips PM3215 50mhz oscilloscope - ground not present
Post by: Aisalord on September 30, 2020, 12:55:24 pm

Hi all!
I bought the oscilloscope in the subject some days ago on ebay, with a complete set of manuals (user and service) and a pair of probes. The machine has a two pole alimentation plug, so there is no ground like the modern ones (It was the 1981 baby...). When I take a measure in the DC part of a circuit that is fed by a switching power unit (or generally, that has a connection to ground) I must pay attention as stated in the Youtube episone #279 (how not to blow up your oscilloscope) or I can measure everything everywhere I want because my oscilloscope is not grounded (obviously not measuring the live wire from the AC with the negative crocodile of the pole, off course!)
Thanks a lot

Title: Re: old philips PM3215 50mhz oscilloscope - ground not present
Post by: Benta on September 30, 2020, 05:29:43 pm

The PM32xx series of oscilloscopes has a double-isolated power supply with no earth connection. I had a PM3212 myself once (20 MHz).
The floating nature of the scope can be useful in certain situations, but can also lead to very dangerous situations.

Think very carefully about what you do.