Download ETEE3212 Spring 2006 Test #2

ETEE3212
Spring 2006
Test #2
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. (35 points) Determine the low frequency
response of the EF amplifier shown to the
right if R1=20kΩ, R2=2kΩ, RL=100Ω,
RE=50Ω, RS=1kΩ, CB=100µF, CE=3.3µF,
Vcc=10V, β=200, VBE=0.7V and VT=26mV.
2. (30 points) Given a common emitter amplifier
with
RS=5kΩ,
RE=500Ω,
R1=19.5kΩ,
R2=185kΩ, RC=RL=10kΩ, CB=4µF, CC=0.2µF,
VCC=12V, VBE=0.7V, and β=200, find CE such
that the low frequency cutoff is approximately
40Hz. Use VT=26mV.
3. (35 points) Design a single 741 op-amp amplifier (Go=105, Ro=75Ω) which will yield an
output given by
vout= 5v1 + 4v2 - 10v3 + 2v4
The equivalent resistance and the negative and positive terminals is 12kΩ. Determine each
resistor value, the input resistance at each amplifier input, and the output resistance. Draw the
schematic and show the resistor values.
Extra Credit (Maximum 25 points): Two differential voltages, vA and vB, each of which are
balanced with respect to ground, are available as inputs. The vA source has a Thevenin resistance
beween 10kΩ and 210kΩ, whereas the vB source has a Thevenin resistance between 50kΩ and
150kΩ. Design a multiple 741 circuit to generate the voltage
vout = 10(vA-vB),
with respect to ground without coupling between the two input sources. The bias current balance
should be as good as is possible.