Question 1

Which power amplifier can deliver maximum load power?

Accepted Answer

Since efficiency of class C operation is high, maximum load power is delivered.

Question 2

A half wave diode circuit using ideal diode has an input voltage 20 sin ωt volts. Then average and rms values of output voltage are

Accepted Answer

and VC = 0.5 x 20 = 10 V.

Question 3

In figure v1 = 8 V and v2 = 8 V. Which diode will conduct?

Accepted Answer

Both D1 and D2 are forward biased.

Question 4

Negative feedback reduces noise originating at the amplifier input.

Accepted Answer

It has no effect on noise originating at amplifier input.

Question 5

Which of the following oscillators is suitable for frequencies in the range of mega hertz?

Accepted Answer

Only LC oscillators are suitable for MHz range.

Question 6

In figure the saturation collector current is

Accepted Answer

Since IE ≂ IC, .

Question 7

In figure what is value of IC if βdc = 100. Neglect VBE

Accepted Answer

Since IB = 100 μA, IC = βIB = 10 mA.

Question 8

In class C operation of an amplifier circuit, the collector current exists for

Accepted Answer

In class C operation output is in the form of short duration pulses.

Question 9

Assertion (A): For large signal variations an amplifier circuit has to be analysed graphically Reason (R): The output characteristics of a transistor is nonlinear.

Accepted Answer

Since the characteristics is non-linear, graphical analysis is needed.

Question 10

In figure, VEB = 0.6 V, β = 99. Then VC and IC are

Accepted Answer

VC = 20 - 1.98 x 10-3 x 5.4 x 103 ≂ 9.3 V.

Question 11

The output V0 in figure is

Accepted Answer

Input to non-inverting op-amp is -10 x 10-6 x 103 = -10 mV. Therefore output = = -100 mV.

Question 12

DC amplifiers have a tendency to be unstable.

Accepted Answer

Due to drift.

Question 13

Study the circuit of figure and examine the following statements It is an active low pass finer. It is a second order filter. The change in gain is 40 dB/decade. Which of the above statements are correct?

Accepted Answer

The circuit is a second order active low pass filter for which gain is 40 dB/decade.

Question 14

The 'h' parameters of the circuit shown in the figure are hib = 25 Ω, hfb = 0.999 and hob = 10-6Ω The Voltage gain is

Accepted Answer

Zi = 25 + 10-6 x 0.99 x 104 ⟹ 25 .

Question 15

A forward voltage of 9 V is applied to a diode in series with a 1 kΩ load resistor. The voltage across load resistor is zero. It indicates that

Accepted Answer

Since load voltage is zero, the current is zero and diode is open-circuited. If load was open-circuited, load voltage would be about 9 V.

Question 16

To prevent a DC return between source and load, it is necessary to use

Accepted Answer

Capacitor offers infinite impedance to DC.

Question 17

The self bias provides

Accepted Answer

Stable Q point is the advantage of self bias circuit.

Question 18

The quiescent collector current IC, and collector to emitter voltage VCE in a CE connection are the values when

Accepted Answer

Quiescent-operation means operation when ac signal is not applied.

Question 19

Figure shows the self bias circuit for CE amplifier and its equivalent circuit. VBB and RB respectively are

Accepted Answer

.

Question 20

In a circuit of figure, Vs = 10 cos(ωt) power drawn by the 2Ω resistor is 4 watts. The power factor is

Accepted Answer

Vs = 10 cos ωt, Let I be the current, then P = I2 R I is the rms current. ⟹ Prms = I2 R ⟹ 4 ⟹ I2 = 4 ⟹ I = 2A. Total power drawn = Vm Im cos θ ⟹ 10 x 2 cos θ = 10 cos θ Total power cannot be determine until value of R = 12 Ω is given.

Analog Electronics Questions