Download ETEE3212 Spring 2006 Test #1

ETEE3212
Spring 2006
Test #1
Name:________________________
Show all work. Clearly indicate final answer(s).
CHEATSHEET MUST BE TURNED IN WITH TEST OR A ZERO WILL BE
RECEIVED FOR ENTIRE TEST!
1. (30 points) Design a CE amplifier using a Darlington
transistor pair with a combined β=25000 and VBE=1.2V
as shown in the circuit to the right. Use VCC=20V,
RE=200Ω, RL=5kΩ, AV= -120V/V and Ai=200A/A.
Assume ideal capacitors and determine:
a. R1, R2 and Rin
b. Maximum undistorted output swing
c. Input dc power required
2. (40 points) Design a circuit as shown
in the figure to the right for maximum
output voltage swing. The transistors
Q1 through Q3 each have β=100 while
Q4 has a β=200. VBE =0.6V for all
transistors and VT=26mV. Assume
ideal capacitors and determine:
a. RC and CMRR
b. Differential mode voltage gain
and common mode voltage
gain for the total system
c. Differential mode input voltage
(vdi) for maximum output
3. (30 points) Consider the modified op-amp
model with G=105, Ri=1MΩ and RCM=200MΩ.
Solve the network of the figure to the right for
the resistance Rout. Hint: Draw the model and
use the Rout=vtest/itest method.
Extra Credit (Maximum 25 points)
An emitter resistor amplifier is being
designed for the unheated tail section of
an aircraft where the temperature ranges
from +50oC to -50oC. The battery source
is 24V, the transistor selected has a β
variation of 300 to 500, and
What
is
the
ICBO(25oC)=0.6µA.
maximum output voltage swing for a
voltage gain of -10V/V if the load is 1kΩ? Let VBE=0.7V and assume ideal capacitors.