# Bipolar Transistor Question

Thread Starter

#### andrewmul

Joined May 7, 2007
1
Hi, so i'm stuck on this question, tis the first time i've attempted one like this. From reading I thinking its referring to a common-collector amplifier circuit but other than that I am stuck on what to do, any help will be greatly appreciated

Design the bias circuit for a bipolar amplifier operating from a supply voltage of 10 V, with a collector current of 1 mA at 300 K. Assume the transistor forward gain b = 200 and its reverse saturation current of the ideal emitter-base diode is 0.1 pA.

a) Find its voltage gain in dBs when driving a load resistance of 1 kOhm.
b) How would the design be affected if the forward gain beta was only 160 ?
c) Redesign the bias circuit to improve the sensitivity of circuit performance to variation in b, and quantify the improvement.
[6 marks ]

I have spent the last 2 hours reading up on transistors. I worked out the base current from the equation beta = Ic/Ib
then as i know Rload I drew out the circuit for a common collector amplifier circuit, then i kind of confused myself In working out the voltage gain and wasnt sure whether 0db was the right answer. Also i was not sure about waht the reverse saturation what part that plays. Im using a NPN transistor in the circuit