AP ECET EEE 2017-9

1. The Barkhausen criterion for sustained oscillations is

A. Aβ=1
B. |Aβ|≥1
C. |Aβ|≤1
D. ∠Aβ=180∘

Answer : Aβ=1
Explain:-

2. In an RC phase shift oscillator, the minimum number of RC networks to be connected in cascade will be

A. One
B. Two
C. Three
D. Four

Answer : Three
Explain:-

3. The decimal equivalent of the hexadecimal number (BAD)16 is

A. 111013
B. 5929
C. 3416
D. 2989

Answer : 3416
Explain:-

4. The function F= ABC' + ABC + A'BC + A'BC' can be reduced to which one of the following

A. F=A
B. F=AB
C. F=ABC
D. F=B

Answer : F=B
Explain:-

5. If the output of a logic gate is '1' when all its inputs are at logic '0', the gate is either

A. A NAND or a NOR
B. An AND or an EX-NOR
C. An OR or a NAND
D. An EX-OR or an EX-NOR

Answer : A NAND or a NOR
Explain:-

6. Number of comparators required to build a 5-bit Analog to Digital converter is

A. 5
B. 11
C. 21
D. 31

Answer : 31
Explain:-

7. Power electronic device with poor turn-off gain is

A. A symmetrical thyristor
B. A conventional thyristor
C. Power bipolar junction transistor
D. Gate turn-off thyristor

Answer : Gate turn-off thyristor
Explain:-

8. A thyristor equivalent of a thyratron tube is a

A. SCR
B. UJT
C. DIAC
D. TRIAC

Answer : SCR
Explain:-

9. Which of the following does not cause damage of an SCR/p>

A. High current
B. High rate of rise of current
C. High temperature rise
D. High rate of rise of voltage

Answer : High rate of rise of voltage
Explain:-

10. Which one of the following power semiconductor device has bi-directional current capability

A. SCR
B. MOSFET
C. IGBT
D. TRIAC

Answer : TRIAC
Explain:-