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WorksheetsPower Electronics Test 1 EE2425A
Total questions: 16
Worksheet time: 2hrs 46mins
Name
Class
Date
1.
[3 minutes] Fill in the blank .
Power Electronics circuits involve______________ from one form to another using power semiconductor devices (1 mark)
Power Electronics circuits involve______________ from one form to another using power semiconductor devices (1 mark)
a)
converting mechanical power
b)
transfer heat
c)
converting electrical power
d)
converting electromagnetic field
2.
[3 minutes] Application of power electronics in static system is...... (2 marks)
a)
to convert electrical charge for supplying load demand or for Power Quality (PQ) improvement.
b)
to convert electrical power for supplying load demand or for Power Quality (PQ) improvement.
c)
to manipulate certain parameter for controlling the weight of motors.
d)
to manipulate certain parameter for controlling the speed of motors.
3.
[3 minutes] How to increase the current conducting capability of diode? (1 mark)
a)
connect several diodes in parallel
b)
connect several diodes in series
4.
[3 minutes] The current gain, β of BJT is given by the expression (1 mark)
a)
IC/IB
b)
IC/IE
c)
IB/IC
d)
IE/IG
5.
[3 minutes] The controlling parameter in MOSFET is the......(1 mark)
a)
IG
b)
VGS
c)
ID
d)
VGE
6.
[3 minutes] Which of the following statement is correct for an SCR operating in REVERSE BLOCKING MODE - practical condition (1 mark)
a)
leakage current flows from anode to cathode
b)
no leakage current
c)
leakage current flows from cathode to gate
d)
leakage current flows from cathode to anode
7.
[3 minutes] Three types of common power transistor are.....(1 mark)
a)
Diode, Triac and IGBT
b)
BJT, MOSFET and IGBT
c)
Diode, IGBT and GTO
d)
GTO, MOSFET and IGBT
8.
[5 minutes] A single-phase half-wave type diode rectifier requires __________ number of diode(s) whereas full wave type requires _________ number of diode(s) (2 mark)
a)
4, 1
b)
1, 4
c)
1, 3
d)
3, 4
9.
[5 minutes] For a certain diode based rectifier, the output voltage (average value) is given by the equation 1/2π ∫Vm sin (ωt) dωt ; where the integral (∫) runs from 0 to π. The rectifier configuration must be that of a.... (2 marks)
a)
single phase controlled full wave with R load
b)
single phase uncontrolled full wave with R load
c)
single phase uncontrolled half wave with RL load
d)
single phase uncontrolled half wave with R load
10.
[5 minutes] A single-phase full wave rectifier is a..... (2 marks)
a)
multiple pulse rectifier
b)
single pulse rectifier
c)
two pulse rectifier
d)
three pulse rectifier
11.
[15 minutes] A basic half-wave uncontrolled rectifier is connected to R = 80 Ohm and L = 0.2 H. If Vm = 100 V and ω = 377 rad/s, calculate (a) β (4 marks)
a)
3.7822 rad
b)
3.9082 rad
c)
3.5822 degree
d)
0.3519 rad
12.
[15 minutes] Similar to Q11 (A basic half-wave uncontrolled rectifier is connected to R = 80 Ohm and L = 0.2 H. If Vm = 100 V and ω = 377 rad/s) calculate (b) the average output current (4 marks)
a)
0.3081 A
b)
0.3422 A
c)
0.5579 A
d)
0.3301 A
13.
[15 minutes] Similar to Q11 (A basic half-wave uncontrolled rectifier is connected to R = 80 Ohm and L = 0.2 H. If Vm = 100 V and ω = 377 rad/s) calculate (c) the power absorbed by the RL load (6 marks)
a)
22.0177 W
b)
21.3355 W
c)
20.3452 W
d)
18.3313 kW
14.
[5 minutes] With respect to the given circuit, from ωt = 0 to α, thyristors _____________ block the forward voltage. (3 marks)
a)
T1, T2
b)
T3, T4
c)
T1, T3
d)
T2, T4
15.
[15 minutes] With respect to the given circuit, find the expression for the average value of output voltage when the supply Vs = Vm sin ωt. (3 marks)
a)
(2Vm/π) (1+cosα)
b)
(Vm/π) (1+cosα)
c)
(2Vm/π)cosα
d)
(Vm/π)cosα
16.
[5 minutes] This equation of Vo belongs to.... (6 marks)
a)
Three phase uncontrolled half-wave rectifier with R load
b)
Three phase uncontrolled half-wave rectifier with line inductance and RL load
c)
Single phase uncontrolled half-wave rectifier with R load
d)
Single phase uncontrolled half-wave rectifier with RL load
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