Hi all
I am using this way to measure the voltage and current across different loads (mainly less than 200mA) to study the effect of different load on power factor, current shape etc. So, I am using an auto transformer to reduce the voltage to 24V (or the rated voltage of the secondary transformer) and then step it up to 200V and measure the voltages across the load and current shunt respectively without using differential probe just making sure the ground probe on the same side
the schematic can be found in the attachment.
Oscilloscope is Rigol DS1054z
If you aren't testing any kind of actual device, & you just want to see how the waveforms across different parts of quite simple circuitry are affected by changes in those circuit components, the setup shown in your diagram should be useable.
I assume you want a source of 220v ac which is isolated from the mains, hence the "back to back" transformers.
I am, however, a bit mystified by your reference to an "auto transformer", which is a device with one winding connected across the Mains supply,with this winding being tapped so you can pick off various voltages.
Such a device is not isolated from the Mains.
https://en.m.wikipedia.org/wiki/AutotransformerDo you mean that you are using a tapping on an auto transformer to feed the 24v winding of the 24:220v transformer?
If so, then your diagram is not correct, & there is the possibility of breakdown between the low voltage winding & core of the transformer if one side of it is connected to the 220v live conductor.
I would not recommend using an autotransformer for this reason.
If it is just a terminology error, & you are actually using two normal "back to back" transformers, it seems reasonable to me.
Obviously, you don't want to get hooked up across the 220v you have derived in this manner, but as far as looking at it with a 'scope, I can't really see a problem.
Remember, the probe earth clips are all connected together at the 'scope, so you can't place earth clips in multiple places at the same time, when probing different points of your circuit.
If you do, the result will be " Bang!".
Further results blown up probes, Oscilloscope or yourself!
Many folk on this forum have never worked with electronics which use higher voltage than around 12v, & are, understandably, apprehensive about voltages of the order of 220v.
Greybeards like myself were brought up on tube technology which uses operating voltages similar to, &, in some cases, quite a bit higher than those you propose to use.
On many occasions I have probed anodes with 3 to 4 hundred volts DC on them, whilst trying to find signal voltages of quite low levels..
One thing to check, is the maximum voltages your probe is rated for.
Modern ones are not always as generously rated as the big old Tektronix ones I probed around with in tube gear.