AP ECET EEE 2020-10

1. In a 3-phase full converter the six SCR's are fired at an interval of

A. 120 degrees
B. 30 degrees
C. 60 degrees
D. 45 degrees

Answer : C. 60 degrees
Explanation:-

2. For a full bridge inverter with the following load R=2ohm, Xl=8ohm and Xc=6ohm

A. The output voltage lags the current by 45 degrees
B. The output current lags the voltage by 45 degrees
C. The output current lags the voltage by 90 degrees
D. The output current lags the voltage by more than 90 degrees

Answer : B. The output current lags the voltage by 45 degrees
Explanation:-

3. The principle of three phase cycloconverter is to

A. add and remove number of SCRs
B. keep the firing angle as 0 degree for all the devices
C. vary progressively the firing angle of the devices
D. keep the firing angle as 180 degrees for all the devices

Answer : C. vary progressively the firing angle of the devices
Explanation:-

4. The DC motor terminal voltage supplied by a solid state chopper for speed control purposes varies ______ with the duty ratio of the chopper

A. inversly
B. parabolical
C. indirectly
D. linearly

Answer : D. linearly
Explanation:-

5. SMPS is based on the _________ principle

A. phase control
B.chopper
C. MOSFET
D. Integral control

Answer : B.chopper
Explanation:-

6. _______ is used in the rotating type UPS Sysytem to supply the mains

A. Alternator
B. Self excited DC generator
C. DC Motor
D. Battery bank

Answer : A. Alternator
Explanation:-

7. The 8051 has ______ parallel I/O ports

A. 4
B. 3
C. 5
D. 2

Answer : A. 4
Explanation:-

8. What does the symbol # represent in the instruction MOV A,#55H

A. Indexed data type
B. Indirect data type
C. Direct data type
D. Immediate data type

Answer : D. Immediate data type
Explanation:-

9. How does the microcontroller communicate with the external peripherals/memory

A. Via registers only
B. Via I/O ports
C. Via memory
D. Via counter

Answer : B. Via I/O ports
Explanation:-

10. Which intruction moves an accumulator to the register from the below mentiones memories?

A. MOV A,Rn
B. MOV direct,A
C. MOV Rn,A
D. Mov A, @Ri

Answer : C. MOV Rn,A
Explanation:-