I am studying full-wave rectifier now.

enter image description here

here is the circuit that I made and then I connected oscilloscope between K and L.

As I've learned from the classroom, this circuit has to make full-rectified signal

However, when I measured the voltage between point K and L, I got this result.

enter image description here

I've tried to think what is the problem here, but I can't figure it out. Is it kind of related to floating ground?

I really don't know what's the problem here.

Can you help me please?

thanks ahead. and sorry if I sound like rude...I am studying English as well...

  • \$\begingroup\$ If you measure between K and L, you will only get one trace. Did you by any chance measure K to ground and with the second channel L to ground? \$\endgroup\$
    – winny
    Commented Feb 27, 2017 at 23:26

1 Answer 1


As you surmised you can't easily look at the signals on a scope if the AC source is referenced to ground.

You need to get a floating AC source, for example a secondary on a transformer. The your scope ground can connect to point C or D and measure the voltage at the other points such as G and H.

  • \$\begingroup\$ thank you guys for the reply. I will try both methods you mentioned: changing probes and measuring voltages in different points. thanks again. have a nice day or night \$\endgroup\$
    – yoon
    Commented Feb 28, 2017 at 0:01

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