I am testing a full-wave bridge rectifier built from four diodes. The input is taken from a function generator. The simulated circuit is working (image added).

The problem is that the output I got from the full-wave rectifier is the same as the output from the half-wave rectifier. The negative part of both input and output signals is omitted (images of the circuit and signals displayed on the oscilloscope are added).

Full wave bridge rectifier

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1 Answer 1


Notice how the waveforms are clamped to about 1V negative.

It means that both the signal generator and scope already share a common ground reference. So they are not floating or isolated from each other.

And you have connected the scope ground to output of the bridge rectifier, shorting out one of the diodes, as both sides of the diode are now grounded.

Even if you did not intentionally do any connections between generator and scope ground, they are connected via mains plug earth terminal.

Use a differential measurement method as you can't connect the scope ground to bridge output, as one bridge input is already grounded.


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