FE, fe
h h
Electronic Circuit II ~ Midterm 2013. 10. 30 (Wed) 10:00 – 12:00 total 100 pts
1. (a) (10 pts) For an amplifier circuit below, determine the effective voltage gain (AV,eff) as a function of RS, Zin, Zout, RL and AV. (b) (5 pts) Discuss the requirements for an ideal voltage amplifier.
2. (10 pts) (a) An amplifier has values of Pin = 100 mW and Pout = 100 W. Calculate the dB power gain of the amplifier. (b) A given amplifier has a power gain of Ap(dB) = 3 dB. Calculate the amplifier output power for Pin = 50 mW.
3. (10 pts) Show that the dynamic resistance of the base-emitter p-n junction is given by 25
e
E
r mV
I 4. (a) Draw the AC equivalent circuit (5 pts) and (b) determine the
voltage gain, AV, for the original circuit shown on the right (10 pts).
Assume that
5. (10 pts) Determine the current gain, Ai, for the circuit shown on the right.
10 2 FE E
h R R
7. (10 pts) For the n-channel JFET, (a) explain the relationship between VGS and ID. (b) Explain the relationship between VDS and ID.
6. (10 pts) Draw the JFET schematic symbols for the n-channel and p-channel, respectively.
VGS(off)
IDSS
8. (20 pts) For the n-channel JFET, transconductance curve is shown below (left). (a) For the self-bias circuit (middle), draw the bias line and find the crossing Q-point. (b) For the voltage-divider bias circuit (right), draw the bias line and find the crossing Q-point.
