How to measure a non isolated circuit with a Scope?

[Zedman]

Could someone please tell me how can I check the waveforms in a circuit which is running from a non isolated PSU?
I have an old 2 beam scope and it does not have isolated probes.

thanks,
Zedman

 

[FvM]

Use an isolation transformer for the power supply.

 

[Zedman]

A 1:1 transformer on the 220V side?
Are there any other methods?

 

[max0412]

You could at your own risk take a differential (non ground referenced measurements) CH1-CH2. Dont attach your probes ground lead and be sure your probes are rated for the voltage your measuring (100x probe).For a 50Hz signal your scope should produce an accurate signal. Just be sure not to exceed the maximum voltage at your scopes input as well.

You really should buy or make your own Iso tranny they aren't that pricey and cheaper then replacing test equipment.