Digital Electronics objective Questions: Part 1

Digital Electronics objective Questions: Part 1

[1] It is required to construct a counter to count upto 100(decimal). The minimum number of flipflops required to construct the counter is

a.  8

b.  7

c.  6

d.  5

Ans:A

 

[2] The gate that assumes the 1 state, if and only if the input does not take a 1 state is 

called........

a.  AND gate

b.  NOT gate

c.  NOR gate

d.  Both b and c

Ans: D

 

[3] For NOR circuit SR flip flop the not allowed condition is....

a. S=0, R=0 

b. S=0, R=1

c. S=1, R=1

d. S=1, R=0

Ans: C . When S=R=1 the output is subject to unpredictable behaviour when 

S and R return to 0 simultaneously.

 

[4] A bistable multivibrator is a

a.  Free running oscillator

b. Triggered oscillator

c.  Saw tooth wave generator

d.  Crystal oscillator

Ans: B

 

[5] For a large values of |VDS|, a FET behave as
a.  Voltage controlled resistor
b.  Current controlled current source
c.  Voltage controlled current source
d.  Current controlled resistor

Ans: C

 

[6] When a step input is given to an op-amp integrator, the output will be
a.  a ramp
b.  a sinusoidal wave
c.  a rectangular wave
d.  a triangular wave with dc bias

Ans: A

 

[7] In a full-wave rectifier without filter, the ripple factor is
a.  0.482
b.  1.21
c.  1.79
d.  2.05

Ans: A

 

[8]Hysteresis is desirable in Schmitt-trigger, because
a.  Energy is to be stored/discharged in parasitic capacitance
b.  Effects of temperature would be compensated
c.  Devices in the circuit should be allowed time for saturation and desaturation
d.  It would prevent noise from causing false triggering

Ans:C

 

[9] For a 10-bit DAC, the Resolution is defined by which of the following
a)  1024
b)  1/1024
c)  10
d)  None

Ans:B

 

[10] SRAM full form is
a)  Serial Read Access Memory
b)  Static Random Access Memory
c)  Static Read-only Access memory

Ans: B

 

[11] What are the minimum number of 2 to 1 multiplexers required to generate a 2 input 

AND gate and a 2 input Ex-OR gate?
A)  1 and 2
B)  1 and 3
C)  1 and 1 
D)  2 and 2

Ans:A

 

[12]The output of a logic gate is ‘1’ when all its inputs are at logic ‘0’. Then gate is either
A)  A NAND or an EX-OR gate
B)  A NOR or an EX-NOR gate
C)  An OR or a EX-NOR gate
D)  An AND or an Ex-OR gate

Ans: B

 

[13] A PLA can be used
A)  As a microprocessor
B)  As a dynamic memory
C)  To realise a sequential logic
D)  To realise a combinational logic

Ans: D

 

[14] A dynamic RAM consists of
A)  6 Transistors
B)  2 Transistors and 2 Capacitors
C)  1 Transistor and 1 Capacitor
D)  2 Capacitor only

Ans:C

 

[15] When a CPU is interrupted, it
A)  Stops execution of instructions
B)  Acknowledges interrupt and branches of subroutine
C)  Acknowledges interrupt and continues
D)  Acknowledges interrupt and waits for the next instruction from the interrupting device.

Ans: B