NPN amplifier

176

03:11:01

In the process of editing a simple two stage NPN transistor amplifier.

published 10 years ago

thebugger

10 years ago

The gain is too high and you're hitting into cut off. Actually the gain is so high that you actually need to decrease the input to 200-300uV to have a clean output. I'd make a few tweaks. First you may start by readjusting the bias. Increase the two 5k resistors to 15k to give the amp more headroom for the swing. You can remove the firat 20uF capacitor and maybe add a series RC chain from the second collector to the first emitter, to decrease the gain.Decreasing the gain, increases the linearity. Also, keep all capacitors above 22uF, to avoid low frequency roll off

thebugger

10 years ago

The RC chain should be 100uF and 2.2k to have a gain of around 3. So with an input of 1V you should get around 3V at the output. I may post a complete circuit if you want?

Aech

10 years ago

I appreciate the quick feedback! I knew the gain of the amplifier was very high, the goal was to hit above 1000. However, I wasn't sure how to edit the output voltage of the AC source, and was changing the value of a DC source then setting it back to an AC source in the hopes that the new output value of the DC source would carry over when I went back to an AC source. However, I have since found out how to edit the output voltage of the AC source, and the amplifier is working as intended.

thebugger

10 years ago

Okay it's a little better but let me make you the complete circuit. I'll make it with a gain of 1000, with an input signal of 1mV, so the output will be around 1V. Search for Preamp for Aech

thebugger

10 years ago

I'll also include an explanation for the various parts of the circuit.

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