1

### NEET 2017

In a common emitter transistor amplifier the audio sgnal voltage across the collector is 3 V. The resistance of collector is 3 k$\Omega$. If current gain is 100 and the base resistance is 2 k$\Omega$, the voltage and power gain of the amplifier is
A
15 and 200
B
150 and 15000
C
20 and 2000
D
200 and 1000

## Explanation

Given: Vi = 3 V, RC = 3 k$\Omega$, RB = 2 k$\Omega$, $\beta$ = 100

Voltage gain of the CE amplifier

AV = $\beta {{{R_c}} \over {{R_b}}}$ = 100$\left( {{3 \over 2}} \right)$ = 150

Power gain = AV$\beta$ = 150(100) = 15000
2

### NEET 2017

Which one of the following represents forward bias diode ?
A
B
C
D

## Explanation

A diode is said to be forward biased if p-side is at higher potential than n-side of p-n junction.
3

### NEET 2016 Phase 1

Consider the junction diode as ideal. The value of current flowing through AB is

A
10$-$1 A
B
10$-$3 A
C
0 A
D
10$-$2 A

## Explanation

Here, the p-n junction diode is forward biased, hence it offers zero resistance.

So IAB = ${{4 - \left( { - 6} \right)} \over {1 \times {{10}^3}}}$ = 10-2 A
4

### NEET 2016 Phase 1

To get output 1 for the following circuit, the correct choice for the input is

A
A = 1, B = 1, C = 0
B
A = 1, B = 0, C = 1
C
A = 0, B = 1, C = 0
D
A = 1, B = 0, C = 0

## Explanation

Output of the circuit, Y = (A + B)·C

Y = 1 if C = 1 and A = 0, B = 1

or A = 1, B = 0 or A = B = 1