But long term, I'd have the company invent in a differential probe. Some more affordable ones are here: **broken link removed**
...thanks, looks good, but the 100MHz "TA042" one costs £330. (I'd need at least 100MHz so as to be able to see, for example, the peak of the drain voltage spike in an offline flyback converter)
I am also concerned that these differential probes dont have BNC connection to the probe...in fact most diff probes dont seem to have this, and it doesnt seem to make sense?
Run power to your project through a 1:1 isolation transformer.
Yes, i'd like to , but 1:1 isolation transformers tend to affect the power meter reading at the mains side of the SMPS..(unless of course , a very expensive isolation transformer is purchased)
As you know, the SMPS is fed like this......230VAC wall socket > autotransformer > Power meter > SMPS.
..We cannot add a 1:1 isolation transformer in here as well, as it will affect the power meter readings, due to the strays of the 1:1 transformer.....(as you know, just feel how hot a 1:1 isolation transformer gets if left plugged in even on no load)
You should be aware as to how much your floating the scope. 30 V or 3000 kV?
Not 3KV, just voltage at primary side of mains powered SMPS. Also, high side Gate drive waveforms of, say, a full bridge converter.
The non-ground connection really makes the differential measurement impossible.
-If i was doing the differential measurement, ie "A-B" or using a diff probe, then i would not need to cut the earth out of the scopes wall plug, i appreciate that.
I have heard that when the scope gets its earth connection cut out of its plug, then any measurements made are affected by the capacitance of the scope "gnd" connection to elsewhere? I am not sure about this though?
I think we have probably all floated a scope to measure something at line voltage, but I hope we all know the risk involved to ourselves and others.
.Thanks, am aware of the safety risk, but does it potentially damage the scope?