Electronic Troubleshooting
ET 198B
Quiz 3
1. Determine the value of R1 for the OP Amp circuit above. If Rf = 10 kΩ and the
gain AV = -18.
ࡾ૚ =
R1 = ___________
૚૙࢑ષ
|ି૚ૡ|
≅ ૞૞૟
2. Determine the value of AV and R1 for the OP Amp circuit above. If Rf = 100 kΩ
and the gain V1 = 10mV and VO = -2.5V.
૚૙૙࢑ષ
R1 = ___________ ࡾ ૚ = |ି૛૞૙| ≅ ૝૙૙
AV = ___________
࡭ࢂ =
ࢂࡻ࢛࢚
ࢂ࢏࢔
ି૛.૞ࢂ
= ૚૙࢓ ࢂ = −૛૞૙
3. Given the above circuit with R1 =2kΩ and RF = 80 kΩ and V2 = 100mV.
Determine VO .
ࡾࡲ
ૡ૙࢑Ω
࡭ࢂ =
+૚=
+ ૚ = ૝૚
ࡾ૚
૛࢑Ω
VO = ___________
ࢂࡻ = ૝૚ × ࢂ૛ = ૝. ૚ࢂ
4. Given the above circuit with V2 = 2.1V. Determine VO .
VO = ___2.1V _____
5.
Given the above circuit, input signal below and Vref = 0V. Draw the output
waveform.
6. Given the above circuit, RF= RB =100kΩ, R1= Ra = 1 kΩ, V1= V2 = 2V.
Assume CMRR =25,000.
Find:
Av : ____________ Av = RF / R1 = 100
Acm : ___________ ࡭ࢉ࢓ =
ࢂࢉ࢓ ࢕
ࢂࢉ࢓
࡭
૚૙૙
࢜
= ࡯ࡹ ࡾࡾ
= ૛૞,૙૙૙ = ૙. ૙૙૝
7. Given the above problem, find CMR
CMR: ____________࡯ࡹ ࡾ = ૛૙ࡸࡻࡳ(࡯ࡹ ࡾࡾ) = ૡૠ. ૢ૟ࢊ࡮ ≅ ૡૡ. ૙ࢊ࡮
8. A given power supply has 12V out without a load and 11.8V out when under
maximum load, what is it’s percent regulation
% ࡾࢋࢍ࢛࢒ࢇ࢚࢏࢕࢔ =
ࢂ࢔࢕ ࢒࢕ࢇࢊ − ࢂࢌ࢛࢒࢒࢒࢕ࢇࢊ
૚૛ − ૚૚. ૡ
× ૚૙૙% =
× ૚૙૙% = ૚. ૟ૢ%
ࢂࢌ࢛࢒࢒࢒࢕ࢇࢊ
૚૚. ૡ
9. Given the above circuit, E=18V, VZ=12.7V, Rs=500Ω, RL=80Ω, β of Q1 = 100,
VBE=0.7V.
Find:
VO : ___________=VZ-VBE1=12.0V
IL : ___________ = VO / RL = 12.0V/80 Ω= 0.15A
Power dissipated in Q1: _____________ = (E - VO) x IL = 6V x 0.15A= 0.9W
10.
What is the purpose of Q3 in the circuit
to the right?
Current limiting to protect during shorts
and other extreme condition
11. Match the following types of switching regulators.
Step Down
Step Up
Inverting
12. What is the voltage across the load in the circuit below?
VL= E +CEMF
13. For the circuit below complete its truth table.
A
0
1
0
1
B
0
0
1
1
C
1
1
1
0
14. For the circuit below and pins 2, 3, 4, 16 set at 5V, pin 15 initially outputting 5V.
What will the out put be on pin 15 just before the sixth clock pulse into pin 1?
Post Clock Pulse
(↓Transistion)
Initial Condition
1
2
3
4
5
Logic Level
Pin 15 (Q)
High
Low
High
Low
High
Low
15. What are the logic levels on each of the pins of the seven segments display, if
the 7490 counter in the drawing below had the following logic levels as outputs:
A=1, B=0, C=1, D=0.
7490 counter output = 5 decimal
7447
Output
pins
13
12
11
10
9
15
14
Display
input
Pin #
1
13
10
8
7
2
11
Logic
Level
Segment
letter
Low
High
Low
Low
High
Low
Low
a
b
c
d
e
f
g