Computer Science questions and answers for interview

1.	A triangular-wave oscillator can consist of an op-amp comparator, followed by a (n)
	A. differentiator B. amplifier C. integrator D. multivibrator Answer: Option C

2.	The circuits in the 8085 that provide the arithmetic and logic functions are called the __________.
	A. CPU B. ALU C. I/O D. bus decoder Answer: Option B

3.	The unit for frequency is the
	A. hertz B. ampere C. watt D. second Answer: Option A

4.	What is the standard TTL noise margin?
	A. 5.0 V B. 0.2 V C. 0.8 V D. 0.4 V Answer: Option D

5.	A pn junction allows current flow when
	A. the p-type material is more positive than the n-type material B. the n-type material is more positive than the p-type material C. both the n-type and p-type materials have the same potential D. there is no potential on the n-type or p-type materials Answer: Option A

6.	In a PLL, to obtain lock, the signal frequency must:
	A. come within the lock range B. be less than the capture frequency C. come within the capture range D. be greater than the capture frequency Answer: Option C

7.	Typical isolation amplifiers use optical coupling.
	A. True B. False Answer: Option B

8.	The largest branch resistance in a parallel circuit carries the largest branch current.
	A. True B. False Answer: Option B

9.	The input impedance is ______ for the amplifier in the given circuit. The data sheet values are Zin = 3 M, Zout = 80 , and Aol = 250,000.
	A. 4.7 k B. 22.7 k C. 3 M D. 68.6 k Answer: Option A

10.	A virtual ground is a(n) ______ ground because this point is at zero volts.
	A. ordinary B. voltage C. chassis D. earth Answer: Option B

11.	A NAND gate has:
	A. LOW inputs and a LOW output B. HIGH inputs and a HIGH output C. LOW inputs and a HIGH output D. None of the these Answer: Option C

12.	What is the current through the capacitor in the given circuit?
	A. 3.5 mA B. 5.5 mA C. 9 mA D. 11.4 mA Answer: Option A

13.	The 555 timer can be used in either the bistable mode or the monostable mode.
	A. True B. False Answer: Option B

14.	A transformer turns ratio of ________ will be needed to match an output impedance of 5 k to an 8 speaker.
	A. 5:1 B. 8:1 C. 25:1 D. 625:1 Answer: Option C

15.	In a transistor, collector current is controlled by:
	A. collector voltage B. base current C. collector resistance D. all of the above Answer: Option B

16.	A 24 V peak source is connected across a 900 H inductor. If the frequency of the source is 22 kHz, what is the reactive power?
	A. 2.3 VAR B. 4.6 VAR C. 9.3 VAR D. 0 VAR Answer: Option A

17.	VCE approximately equals _______ when a transistor is in saturation.
	A. VCC B. VB C. 0.2 V D. 0.7 V Answer: Option C

18.	If a 100 resistance is connected to a 100 capacitive reactance in a series RC circuit, the impedance equals 200 .
	A. True B. False Answer: Option B

19.	To reduce the number of pins on the IC package, manufacturers often use ___________.
	A. MOSFET architecture B. address multiplexing C. address decoding D. address demultiplexing Answer: Option B

20.	What is the voltage across the inductor in the given circuit on the falling edge of the first input pulse?
	A. –0.2 V B. 0.2 V C. –9.8 V D. 9.8 V Answer: Option A