Quote:
Originally Posted by old_tv_nut
Looking at Q801, you see that the peak to peak waveform on the base is twice the size of the DC voltage, so this stage is being overdriven to clip the AC waveform. The DC bias uses feedback from the collector load. Given all this, it's likely that any general purpose transistor with a beta of say 100 or greater would work.
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Ok. That's really cool of you to explain that. I think I get it.
I think what you're saying here is that because the voltage threshold is so low, the transistor is only going to turn on when the waveform crosses the conduction threshold. Which would be ~0.7V if the emitter was tied to ground, but it has a 270 ohm resistor there, so I guess it would actually be a little higher than .7 it starts, depending on what the voltage is on the emitter at any given time.
So that means the collector probably has a ~10Vpk squarish waveform with fairly short negative-going pulses when Q801 is in conduction, right?