MEDIUM
Earn 100

A transistor oscillator is

(i) An amplifier with positive feedback

(ii) An amplifier with reduced gain

(iii) The one in which DC supply energy is converted into AC output energy. Then

50% studentsanswered this correctly

Important Questions on Semiconductor Devices and their Applications

EASY

Given below are two statements : One is labelled as Assertion A and the other is labelled as Reason R.

Assertion(A) : n-p-n transistor permits more current than a p-n-p transistor.

Reason(R) : Electrons have greater mobility as a charge carrier.

HARD
A realistic graph depicting the variation of the reciprocal of input resistance in an input characteristics measurement in a common emitter transistor configuration is :
MEDIUM
A common emitter amplifier circuit, built using an NPN transistor, is shown in the figure. Its dc current gain is 250RC=1  and VCC=10 V . The minimum base current for VCE to reach saturation is

Question Image
MEDIUM

The transfer characteristic curve of a transistor, having input and output resistance 100 Ω and 100 kΩ respectively, is shown in the figure. The voltage and power gain, are respectively:
Question Image

EASY

The transfer characteristics for a transistor in CE mode is as shown in figure. To use transistor as a switch, it should be used in

Question Image

MEDIUM
An NPN transistor is used in common emitter configuration as an amplifier with 1 kΩ load resistance. Signal voltage of 10 mV is applied across the base-emitter. This produces a 3 mA change in the collector current and 15 μA  change in the base current of the amplifier. The input resistance and voltage gain are:
EASY
The ratio (R) of output resistance r0, and the input resistance ri in measurements of input and output characteristics of a transistor is typically in the range :
HARD

Question Image

In the circuit shown, the value of β of the transistor is 48. If the supplied base current is 200 μA, what is the voltage at the terminal Y?

MEDIUM

An n-p-n transistor has three leads A, B and C. Connecting B and C by moist fingers, A to the positive lead of an ammeter, and C to the negative lead of the ammeter, one finds large deflection. Then, A, B and C refer respectively to :

EASY
For a common emitter configuration, if α and β have their usual meanings, the correct relationship between α and β is:
MEDIUM

The output characteristics of a transistor is shown in the figure. When VCE is 10V and IC=4.0mA, then value of βac is 

Question Image   

EASY
For transistor action, which of the following statements is correct?
EASY
For a transistor to act as a switch, it must be operated in
MEDIUM

In the following common emitter circuit, β=100 and VCE=7 V. If VBE is negligible, then the base current is

Question Image

EASY
For a CE transistor amplifier the audio signal voltage across the collector resistance of 2kΩ is 2 V. The current amplification factor of the transistor is 100 . If the base resistance is 1kΩ, the input signal voltage and base current are respectively
EASY
In a transistor circuit, the collector current is changed by 89 mA, if the emitter current is changed to 9.0 mA. The value of current amplification factor, β is
EASY
An unknown transistor needs to be identified as a npn or pnp type. A multimeter, with +ve and -ve terminals, is used to measure resistance between different terminals of transistor. If terminal 2 is the base of the transistor then which of the following is correct for a pnp transistor?
MEDIUM

In the figure, given that VBB supply can vary from 0 to 5.0 V, VCC=5 V, βdc=200, RB=100 , RC=1  and VBE=1.0 V. The minimum base current and the input voltage at which the transistor will go to saturation, will be, respectively:

Question Image

EASY
Transfer characteristics [output voltage V0 vs input voltage Vi] for a base biased transistor in CE configuration is as shown in the figure. For using transistor as a switch, it is used

Question Image