Electronics

Question 1

Contact potential of a pn junction has 0.6 volts at equilibrium temperature 50° C. n 1 = 1.5 x10 ^10 1/cm^3 (intrinsic carrier concentration), donor concentration in n type material is7 cross times 10 to the power of 17 space 1 divided by cm cubed. Find acceptor concentration:

A. 7.0 x 10 ^10 1/cm^3
B. 1.0 X 10^11 1/cm^3
C. 7.2 x 10^11 1/cm^3
D. 7.0x10^17 1/cm^3

Answer 1

Correct Option: C

Question 2

A P-channel junction gate field-effect transistor (JFET) is operating in the saturation region. The drain-to-source current is 500 mA, the pinch-off voltage is 2.5 V, and the drain current is 34.5 mA. Most nearly, the small-signal transconductance is:

A. 0.24 mS.

B. 42 mS.

C. 110 mS.

D. 150 mS.

Answer 2

Correct Option: C

Question 3

Calculate common mode rejection ratio (CMRR), of non-ideal operational amplifier with a differential gain of 50 and a common mode gain of 5.

A. 100,000 dB

B. 100 dB

C. 20 dB

D. 5 dB

Answer 3

Correct Option: C

Question 4

When a diode is reverse biased, the voltage at the cathode is:

A. equal to the voltage at the anode.

B. zero.

C. greater than the voltage at the anode.

D. less than the voltage at the anode

Answer 4

Correct Option: C

Question 5

Positive feedback tends to result in:

A. reduced system noise.

B. system instability.

C. system oscillations.

D. both B and C

Answer 5

Correct Option: D

Question 6

An ideal operational amplifier (op amp) has which of the following characteristics?

I. Infinite open loop gain
II. Zero positive gain
III. Infinite input impedance
IV. Infinite output impedance
V. Zero output impedance
VI. Zero input impedance
VII. Infinite bandwith

A. I, III, V, and VII

B. I, VI, IV, and VII

C. II, III, IV, and VII

D. I, III, IV, and VII

Answer 6

Correct Option: A

Question 7

How many decibels from the peak of an energy signal can determine half-power bandwidth?

A. 3 dB

B. 0.5 dB

C. 1 dB

D. 5 dB

Answer 7

Correct Option: A

Question 8

Find common-mode rejection ratio (CMRR) in decibels of a bipolar junction transistor (BJT) differential amplifier with a differential gain of 16 and a common-mode gain of 60.

A. -21.41

B. 36.42

C. -11.48

D. 0.26

Answer 8

Correct Option: C

Question 9

What is the average DC voltage output of a 4-pulse rectifier when the line-to-line RMS voltage input is 200 V? Assume no output filter.

A. 4.93 V

B. 100.5 V

C. 254.7 V

D. 301.2 V

Answer 9

Correct Option: C