Question 1

The load impedance ZL of a CE amplifier has R and L in series. The phase difference between output and input will be

Accepted Answer

It is 180° for purely resistive load and between 180° and 270° for R-L load.

Question 2

An amplifier with loop gain Aβ will be more stable for value of Aβ as

Accepted Answer

A feedback amplifier is stable if loop gain is less than unity. More less, more stable, hence β will be more stable.

Question 3

A bridge rectifier circuit has input of 50 Hz frequency. The load resistance is RL and filter capacitance is C. For good output wave shape, the time constant RLC should be at least equal to

Accepted Answer

Time constant RLC must be about 5 x 20 ms.

Question 4

In figure The minimum and maximum load currents are

Accepted Answer

When RL = ∞, IL = 0, When RL = 100 Ω, or 120 mA.

Question 5

An exponential amplifier has diode in feedback path.

Accepted Answer

It has resistance in feedback path.

Question 6

Consider the following statements : A clamper circuit adds or subtracts a dc voltage to a waveform does not change the waveform amplifiers the waveform Which are correct?

Accepted Answer

Clamper does not amplify the waveform. Hence 1 and 2 are correct.

Question 7

Gain of the amplifier is 'A'. Then the I/P impedance and O/P impedance of the closed loop amplifier shown below would be

Accepted Answer

By using Miller theorem circuit can be redrawn as .

Question 8

In a CE amplifier the input impedance is equal to the ratio of

Accepted Answer

Input is applied to base with emitter grounded. The input impedance is the ratio of ac base voltage to ac base current.

Question 9

A CB amplifier has re = 6 Ω, RL = 600 Ω and a = 0.98. The voltage gain is

Accepted Answer

Analog Electronics Questions