WorksheetsCHOPPER 3
Total questions: 20
Worksheet time: 11mins
Identify the given circuit
type D chopper
Two quadrant type C chopper
type E chopper
type F chopper
A type C chopper consists of __________ diodes and _________ switches in anti-parallel.
2, 2
3, 3
4, 4
3, 4
What is the duty cycle of a chopper ?
Ton/Toff
Toff x Ton
T/Ton
Ton/T
The semiconductor devices can be used as a switch in DC chopper except
IGBT
MOSFET
DIODE
SCR
Variable frequency control is known as
pulse width modulation
frequency modulation
analog modulation
digital modulation
A type C chopper can operate in
Ist and IInd quadrants
IInd and IIIrd quadrants
Ist, IInd and IIIrd quadrants
four quadrants
For the first quadrant operation of type E chopper
Only CH1 is on
CH1 and CH2 is on
CH1 and CH3 is on
CH1 and CH4 is on
For a type E chopper, when CH2 is first on and then switched off then the
power flows from source to load
power flows from load to source
load is short circuited
none of the mentioned
What is the expression for load voltage when the chopper is operated in the second quadrant?
Vs
E
0
E + Ldi/dt
The load emf E must be reversed for
first and second quadrant operation
third quadrant operation
fourth quadrant operation
both third and fourth quadrant operation
In a type E chopper, if all the four chopper switches are closed simultaneously then
load is short circuited
supply is short circuited
both load and supply are shorted
In a type-D chopper
current can flow in both the directions of the load
current cannot flow in both the directions of the load
voltage can only be positive
voltage can only be negative
What is the load voltage value when both the chopper switches are on?
0
Vs
2Vs
Vs/2
For a type D chopper, the average value of output voltage will be positive when
Ton = Toff
Ton < Toff
Toff = 0
Ton > Toff
For a type D chopper, if duty cycle α < 0.5 then the
average voltage is positive
average voltage is negative
average voltage is zero
Which type of chopper is used in the regenerative braking of DC motors?
type A
type B
type C
type D
In a type C chopper, if only one switch is operated
only one quadrant operation will be obtained
two quadrant operation can be obtained
the chopper won’t work
In case of TRC (Time Ratio Control), _________ is varied
duty cycle
firing angle
supply frequency
supply voltage magnitude
In case of frequency modulation system, ________ is kept constant.
T
Ton
Toff
Either Ton or Toff
In pulse width modulation scheme, _________ is kept constant.
Vs
Ton
T
Toff
