Setting the Q-point of transistor with a voltage divider - 5V Ucc

124

01:39:14

Setting working point (aka Q-point) of a transistor with a voltage divider. Question: How can I make the signal symmetrical to 0V and less distorted? Any insight is appreciated.

Answer:
1. Reduce input voltage from 1V to 5mV. I found that reduction from 1 V to 100 mV also worked. --- This is the most important. Transistor was saturated at 1 V input.
2. Reduce load from 500 kOhm to 10kOhm. This made the output signal symmetrical to 0 V. 
3. Fix to standard  Re=200 Ohm and Rc=1.2 kOhm resistor values.
This results in amplifying AC with an amplitude of 5 mV to 40 mV (8x amplification) at 1 kHz.
Thanks for everyone's help! :)

published 8 years ago

crake

8 years ago

You're wayyy over driving this circuit with 1V input signal

crake

8 years ago

Q point looks pretty good. I'd drop 1V across Re, though. The cap will make your output symmetrical as the DC portion of the signal is removed

crake

8 years ago

Drop the input signal down to 5mV

jason9

8 years ago

Drop the input to 5mV and increase the left capacitor to 47uF and the middle one to 2.2mF. You might also consider dropping the load (far right resistor) to 10kOhm to be more realistic while also not straining the amplifier significantly.

acser123

8 years ago

Thank you, everyone!

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