Oscilloscope Anomaly

[jedro]

I have a permanent magnet alternator connected to a bridge rectifier. No electrical load is applied.

If I measure just the AC voltage and waveform, all is well. If I measure just the DC voltage and waveform, all is well.

However, if I try and measure both AC and DC at the same time the rectifier starts to get hot. The test leads start to warm up.

Any ideas as to what is happening or what am I doing wrong? Thanks.

 

[bertus]

Hello,

When you want to measure the AC and DC at the same time, probably D2 gets shorted. ( I assume you use the bottom red line as ground.)

Bertus

 

[jedro]

Thanks. I don't recall on which AC line the ground clip on the test probe was connected. I did not think that it mattered. I will retest, hoping that I don't take out my scope.