Hello there, newbie here

I'm using a signal generator for analysis of a rectifier circuit, and has you know "normally" a signal generator is single ended (between a point and the mass), which is not desirable for the experiment. So basically i have to converted to Double-ended (between two points that does not include the mass) that way i can observe i can use the oscilloscope to see the voltage in the nods of the rectifier circuit.
One way that i think i can solve it is by using a Isolation Amplifier with an unity gain connected to the end of the signal generator that will produce a double-ended signal.

Any thoughts, examples, etc.?

Best Regards
Amaury

 

By mass you mean PE? I am not sure but I think generators usually have a floating output, so you should have no trouble using the signal where you want.
If the output is tied to PE, you can use an isolation transformer to power that instrument, or disconnect the PE wire, but beware that this is could be dangerous if you are probing anything else then safe low voltage circuits.

Also it is a good idea to post a picture of what you are trying to measure and how.

 

By mass you mean PE? I am not sure but I think generators usually have a floating output, so you should have no trouble using the signal where you want.
If the output is tied to PE, you can use an isolation transformer to power that instrument, or disconnect the PE wire, but beware that this is could be dangerous if you are probing anything else then safe low voltage circuits.

Also it is a good idea to post a picture of what you are trying to measure and how.

PE? Excuse me but it's missing my mind, what that means, and i mean earth of the generator, which is different from the rest of the circuit. But anyways it's an old generator and you cannot send signal if not sing it's own earth.

Thanks for the reply

 

PE means protective earth, that is in your wall socket green-yellow wire (or just green or bare in the US i think).
You mean the ground pin of the output is connected to PE? Posting the type of the generator will help too.

 

Isolation Transformer ...
https://www.allaboutcircuits.com/technical-articles/transformer-isolation/

 

PE means protective earth, that is in your wall socket green-yellow wire (or just green or bare in the US i think).
You mean the ground pin of the output is connected to PE? Posting the type of the generator will help too.

Yes, yes it is connected to PE.
Doing a quick research i found that i may use this (image bellow), but i actually cant really understand it. So have to research more

 

Doing a quick research i found that i may use this

That will only output a low level (a few millamps) signal.
You would need to add a couple amplifiers on the output.

How high a frequency and voltage do you want to test with?

 

That will only output a low level (a few millamps) signal.
You would need to add a couple amplifiers on the output.

How high a frequency and voltage do you want to test with?

it will not be a lot, up to 20V, 50MHz are the boundaries. So i guess the circuit wont work ?

 

If the circuit will work or not really depends on the circuit being measured, and what is the voltage difference between the scope ground and the generator ground.
If you just want to have a simple mesurement on a 50hz rectifier, then I strongly suggest you use a low voltage transformer instead of the generator. You will then not need to be concerned with this issue.
But as I said earlier, the more you tell us about what are you actually measuring the better we can suggest the easiest method to do so.

 

it will not be a lot, up to 20V, 50MHz are the boundaries.

I would not describe that as "not be a lot".
20V @ 50MHz is not trivial to generate.
What type of rectifier circuit needs to operate at those limits?

 

If the signal generator is being used at a small range of frequencies then a transformer suitable for that frequency range is the best choice, since it can provide quite a lot of isolation. But you will need to verify that the driving wave form to your experimental circuit is not distorted because distortion will alter the results that you see. Understanding that can save you from a lot of embarrassment of publishing incorrect results.

The amplifier circuit shown does not really provide isolation from common, it does provide balanced signals. which may be useful, but they are not really isolated, since both of the output signals are referenced to the common "ground" voltage point.

 

Please delete.

"Please Delete"??? Who should delete WHAT?? Some of the comments are off-base but none bad enough to demand deletion. OR is the request to delete the whole thread? Or just my last post?? Or has whatever been posted already been deleted??

 

With the proper selection of u material cores, one could assemble a set of transformers(baluns) to cover up to 50 MHz.

An auto transformer configuration can also give you unbalance to balance.

You could purchase off the shelf.

 

"Please Delete"??? Who should delete WHAT?? Some of the comments are off-base but none bad enough to demand deletion. OR is the request to delete the whole thread? Or just my last post?? Or has whatever been posted already been deleted??

He just asked to deleted his own posted, that's it, and I just deleted the post as his requested.

 

With the proper selection of u material cores, one could assemble a set of transformers(baluns) to cover up to 50 MHz.

An auto transformer configuration can also give you unbalance to balance.

You could purchase off the shelf.

An autotransformer or a balun will not provide any isolation. Yes they provide a balanced output but no isolation at all.

 

I probably mis-understand what his problem is. He explains it as an isolation problem, but it sounds like a signal reference problem.

But I do not understand the 20V and 50 MHz spec.

My Carnac is not working.

 

I probably mis-understand what his problem is. He explains it as an isolation problem, but it sounds like a signal reference problem.

But I do not understand the 20V and 50 MHz spec.

My Carnac is not working.

That is the frequency and voltage of the waveform being rectified , which tells us that this is not a package directly fed by the "mains". It sounds a bit more like a high efficiency switching power supply.

 

I think that is the max capability of his signal generator.

 

What is the problem?

Is it to build an amplifier for his signal generator?

OR,

Is it to get a differential signal from his signal generator to an amplifier/rectifier that he is building?

 

Revisiting post #8, it seems that indeed those are probably the frequency limits of the signal generator. So now we once again have the condition of a question asked without any adequate information provided as to just what needs to be answered. The amplifier circuit in post #6 does provide a balanced signal, but that signal is certainly ground referenced, not isolated from ground. What is not provided is any description of what frequency test results are supposed to be obtained at. The simple true isolation method would be a transformer, but there are no simple transformer schemes that cover all frequencies. This makes suggesting a transformer type a "best guess" at best. So the Thread Starter, (TS for short) wants a useful answer then we need to know the frequency that the isolated signal will be, at least some approximate range, or a more detailed description of just what information the testing process is hoped to provide.