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BJT Circuit

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Please see the attachment for circuit diagram, where

R1 =91k ohms
R2 = 20k ohms
Rc = 5K ohms
Re = 1k ohms.

Now add a capacitor from emitter to ground, and size it to give a 3 db attenuation in gain to the collector at 1 kHz, relative to gain at a higher frequency where the gain does not change with frequency. What size is the capacitor? Does the input capacitor size have to change, and if so, to what value? What are the new voltage gain and input and output impedances? Assume that the circuit is driven from a 50 Ohm source resistance generator. What is the (rms) voltage noise at the base from 1 kHz to 11 kHz frequency? What is this noise referred to the output?

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Solution Preview

Please see attached file for the solution to the given problem.

Solution: The addition of Ce causes a bypass effect on Re from the cutoff frequency and up. Solving first for the resistance as seen from the emitter terminal, we have:

Using the value of IE = 1mA, then r'e = 25 ohms. Then from the ...

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