Q.1.
The below given circuit can
- a) operate in all the four quadrants
- b) operate in only the first and second quadrant
- c) operate in only the fourth and third quadrant
- d) operate in only the first and fourth quadrant
Q.2.
In the below shown chopper circuit, when CH3 is on
- a) both load voltage and current are zero
- b) both load voltage and current are positive
- c) both load voltage and current are negative
- d) none of the mentioned
Q.3.
In the below given type E chopper circuit, when CH3 and CH2 are switched on and then CH3 is switched off after some time, then
- a) load current falls to zero
- b) negative current freewheels through CH2, D4
- c) positive current freewheels through CH2, D4
- d) none of the mentioned
Q.4.
For the type E chopper to be operated in the fourth quadrant
- a) only one switch is operated
- b) two switches are operated
- c) three switches are operated
- d) all the switches are operated
Q.5.
For the fourth quadrant operation, the current flows through
- a) CH1, D2, L and D1
- b) CH4, D3, L and D4
- c) CH4, D2, L and E
- d) CH1, D2, L and D3
Q.6.
When CH4 is turned on and then off
- a) load current falls to zero
- b) negative current freewheels through D2, D3
- c) positive current freewheels through D2, D3
- d) none of the mentioned
Q.7.
Find the expression for the ripple factor in terms of duty cycle α for a type A step down chopper
- a) √(1-α/α)
- b) α2/2
- c) √α/2
- d) √(1-α)
Q.8.
The AC ripple voltage is given by
- a) Vrms/Vo
- b) Vrms2/π
- c) √(Vrms2 – Vo2)
- d) √(Vrms + Vo)
Q.9.
The expression for the thyristor (chopper switch) current is given by
- a) 2Vs/π
- b) 180°
- c) E/2Vs
- d) Vs/R
Q.10.
In a type E chopper, if all the four chopper switches are closed simultaneously then
- a) load is short circuited
- b) supply is short circuited
- c) both load and supply are shorted
- d) none of the mentioned.
Q.11.
A type A step down chopper has Vs =V and is connected to RLE load. With R = 1 Ω, E =V and L large enough to maintain continuous conduction. Find the average value of load current for a duty cycle of%.
- a) 100 A
- b) 22 A
- c) 42 A
- d) 16.5 A
Q.12.
A step down chopper has Vs =V and is connected to RLE load. With R = 1 Ω, E =V and L = 5 mH. The chopping period isμs and the on-period isμs. Find the value of minimum steady state output current.
- a) 33 A
- b) 42 A
- c) 0 A
- d) 51 A