"Electronics Question and answer for u"

ELECTRONICS

Electronic Devices Objective Questions

[1] For harmonic generation the amplifier used is
a)Audio Amplifier
b)Class-A Amplifier
c)RC Amplifier
d)class-C Turned Amplifier

Ans:D

[2] Zener diodes semiconductors are
a)Lightly Doped
b)Heavily Doped
c)Medium Doped
d)Not at all Doped

Ans: B

[3] In FET amplifiers, input is Incorrect!
a)A current signal
b)A voltage signal
c)Either a current or voltage signal
d)None of these

Ans: B

[4] H-parameters of a transistor
a)Are constant
b)Vary with temperature
c)Are dependent upon collector current
d)None of these

Ans:C

[5] In a voltage series feedback
a)Output resistance increases while input resistance decreases
b)Output and input resistances are reduced
c)Output and input resistances are increased
d)Output resistance decreases while input resistance increases

Ans: B

[6]In a saturated transistor
a)B-E junction is forward biased with C-B junction is reverse biased
b)Both the junctions are forward biased
c)B-E junction is reverse biased with C-B junction is forward biased
d)Both the junctions are reverse biased

Ans: B

[7]For an ideal noise free amplifier, the noise figure is
a)Zero
b)Zero dB
c)Infinity
d)1 dB

Ans: B

[8]When a junction is formed between a metal and a semiconductor, the depletion layer is
a)More on the side of the metal
b)Equal on both sides
c)Less on the side of the metal
d)Less on semiconductor side

Ans: C

[9] The impurity commonly used for realizing the base region of a silicon NPN transistor is ______
A) Gallium
B) Indium
C) Boron
D) Phosphorus

Ans: C

[10] A MOS capacitor made using P-type substrate is in the accumulation mode. The dominant charge in the channel is due to the presence of 
A) Holes
B) Electrons
C) Positively charged ions
D) Negatively charged ions

Ans: B

 
[11] A Zener diode works on the principle of ______
A) Tunneling of charge carriers across the junction
B) Thermionic emission
C) Diffusion of charge carriers across the junction
D) Hopping of charge carriers across the junction

Ans: A

 
[12] A BJT is said to be operating in the saturation region if______
A) Both the junctions are reverse biased
B) Base-emitter junction is reverse biased & base-collector junction is forward biased
C) Base-emitter junction is forward biased & base-collector junction is reverse biased
D) Both the junctions are forward biased

Ans: D

 
[13] To obtain very high input & output impedances in a feedback amplifier, the topology used is
A) Voltage-Series
B) Current-Series
C) Voltage-Shunt
D) Current-Shunt

Ans: C

 
[14] Cut off frequency of a bipolar transistor ____
A) Increase with the increase in base width
B) Increase with the increase in emitter width
C) Increase with the increase in the collector width
D) Increase with the decrease in the base width

Ans: D

 
[15] Negative feedback in amplifiers
A) Improves the signal to noise ratio at the input
B) Improves the signal to noise ratio at the output
C) Does not affect the signal to noise ratio at the output
D) Does not affect the signal to noise ratio at the input

Ans: B