To get an output Y= 1 in given circuit which of the following input will be correct ?
A
A $$ \to $$ 1, B $$ \to $$ 0, C $$ \to $$ 0
B
A $$ \to $$ 1, B $$ \to $$ 0, C $$ \to $$ 1
C
A $$ \to $$ 1, B $$ \to $$ 1, C $$ \to $$ 0
D
A $$ \to $$ 0, B $$ \to $$ 1, C $$ \to $$ 0
Explanation
The Boolen expression for the given
combination is
output Y = (A + B) · C
So it is clear that Y = 1,
when A = 1, B = 0 and C = 1
2
MCQ (Single Correct Answer)
AIPMT 2012 Mains
The input resistance of a silicon transistor is 100 $$\Omega $$. Base current is changed by 40 $$\mu $$A which results in a change in collector current by 2 mA. This transistor is used as a common emitter amplifier with a load resistance of 4 k$$\Omega $$. The voltage gain of the amplifier is
The figure shows a logic circuit with two inputs A and B and the output C. The voltage wave forms across A, B and C are as given. The logic circuit gate is
A
OR gate
B
NOR gate
C
AND gate
D
NAND gate
Explanation
The truth table is
The logic circuit is OR gate.
4
MCQ (Single Correct Answer)
AIPMT 2012 Prelims
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
A
in region III
B
both in region (I) and (III)
C
in region II
D
in region I
Explanation
In the given graph,
Region (I) – Cutoff region
Region (II) – Active region
Region (III) – Saturation region
Using transistor as a switch it is used in cutoff
region or saturation region.
Using transistor as a amplifier it is used in active
region.
Questions Asked from Semiconductor Electronics
On those following papers in MCQ (Single Correct Answer) Number in Brackets after Paper Name Indicates No of Questions
