modified 8 years ago

X 100 CE amplifier with better BJT current source

00:55:20

CE amplifier with PNP transistor based 1 mA current source, open loop gain ( with 33K shorted ) is enormous at 288 000 approx ( similar to older opamps ) With feedback resistors shown, the gain is X100 ( 40dB )

I have also added a Darlington buffer which is included within the feedback loop, which should serve to lower the output impedance even more than the buffer on its own.

In reality the open loop gain probably wouldn't be this high due to capacitance in real components, which I don't think is modelled by this simulator 

I built this on 19-6-17 and with the feedback resistors shown I got a gain of around X87.
The open loop gain ( with the 33K shorted ) was between 4000-5000 depending on the test frequency. I used a bc549c for the actual amplifier, a 2n3906 for the current source and a bc517 Darlington  for the output buffer.

published 8 years ago

hurz

8 years ago

To futher simplify it you can check this, which was more for fun. However, you start to be fascinated in BJT circuits, keep it up! http://everycircuit.com/circuit/5225042770132992

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