Class AB Push Pull Amplifier Design

MrAl

Joined Jun 17, 2014
11,494
Sorry, wrong circuit. Quiescent voltage is actually 2.6v and current: 255mA. I am confused - obviously my biasing is wrong??
Hi,

Note here when i speak of Vout i mean the output at the very emitters not the output after the cap because we want to know the DC operating point there.
Well 2.6v with dual 10v supplies is still a lot. 255ma is also way too much.
If you try, you can get both down into the hundreds of femto units like 500 femto volts, maybe 500 femto amps, although for good crossover we usually want at least 1 or 2ma as emitter current not zero, but it's interesting to shoot for zero too.
In theory you can get 0 output voltage and whatever quiescent current you want..
See if you can improve it and how the resistors R2 and R4 interact for example.
if you take first partials of both VoutQ and IoutQ with respect to both R2 and R4 you can see which resistors affect the output more, and iwth a little more trouble you can try to find a min or max. Ultimately you can solve for both of these with 0v out and 2ma emitter current for example.
It is an interesting exercise, but also note this is pure theory here in real life you would probably want one or more adjustments to match to the actual transistors.
 
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