Calculating Current Through a Transistor

[sregor]

OK, here's the other extreme, 3mV bias with a 10kHz signal at 1W output. I don't see anything that even hints at a notch on the zero point. Unless I'm missing something, this doesn't seem to be a valid test to set bias current.

- Pete

View attachment 1645767

Are you running a load? Many amps won't show crossover distortion with no load....

 

[Binkman]

Perhaps refer to my link post #77.

 

[LBPete]

I have been using a dummy load, all of the scope traces I've posted are under load. I did view the video link. It's a good description of bias.

In any case, today I set the bias at 30mA and played it loud. It sounds great, fantastic base response and it didn't break a sweat. The power transistors never went over 100 degrees F. I'm going to call it done. I appreciate everyone's help.

- Pete

 

[gadget73]

If it doesn't show crossover distortion, call it good. The top and bottom peaks of the wave and the downward slop of the waves in that last scope shot look a bit funny to me though. I wouldn't expect the bias setting to cause that but it might be worth looking at.

 

[LBPete]

Those variations are probably due to my vintage function generator and cheap scope probes. Time to move on with this one.

- Pete