AP ECET EEE 2018-10

1. Freewheeling diode in a converter is placed _____

A. In series with each thyristor
B. In shunt with each thyristor
C. Across the DC load impeddance
D. in series with the DC load impedance

Answer : C. Across the DC load impeddance
Explanation:-

2. A cycloconverter is a

A. amplitude chnager
B. phase changer
C. waveform changer
D. frequency changer

Answer : D. frequency changer
Explanation:-

3. In DC chopper, if T is the chopping period, then the output voltage may be controlled by PWM by _____

A. Varying T, keeping TON constant
B. Varying TON, keeping T constant
C. Varying TOFF, keeping T constant
D. Varying T, keeping TOFF constant

Answer : B. Varying TON, keeping T constant
Explanation:-

4. A single phase voltage source square wave inverter feeds pure inductive load. The waveform of the load current will be

A. sinusoidal
B. rectangular
C. trapezoidal
D. triangular

Answer : D. triangular
Explanation:-

5. The PWM control of DC motor varies ____ with speed

A. inversly
B. parabolically
C. exponentially
D. linearly

Answer : D. linearly
Explanation:-

6. SMPS are diased on the ____ principle

A. phase control
B. integral control
C. Chopper
D. MOSFET

Answer : C. Chopper
Explanation:-

7. The number of flags of 8051 is

A. 5
B. 8
C. 2
D. 4

Answer : D. 4
Explanation:-

8. During PUSH instruction, the stack pointer is

A. incremented by two
B. incremented by one
C. decremented by two
D. decremented by one

Answer : B. incremented by one
Explanation:-

9. In 8255, the length of a control word is ____

A. 2 bytes
B. 4 bits
C. 8 bits
D. 12 bits

Answer : C. 8 bits
Explanation:-

10. PIC 8259 is a _____ pin chip

A. 40
B. 28
C. 24
D. 32

Answer : B. 28
Explanation:-