296 + Interview Questions in Digital Electronics in Electronics and Communication Engineering Page 3 InterviewSolution

101.	What will be FSV in 2 bit BCD D/A converter is a weighted resistor type with E = 1V, R = 1 MΩ and R = 10KΩ
Answer» FSV for BCD = (10d - 1)VR. = (102 -1) x .

Discussion

102.	With four Boolean variables, how many Boolean expressions can be performed?
Answer» 224 = 216.

Discussion

103.	A + (B . C) =
Answer» This is distributive law.

Discussion

104.	The number of logic devices required in a Mod-16 synchronous counter are
Answer» 4 flip-flops and 2 AND gates.

Discussion

105.	A 2 bit BCD D/A converter is a weighted resistor type with E = 1V, R = 1 MΩ and R = 10KΩ then Resolution in percent and volt is __________ .
Answer» Resolution % for BCD = where d is Resolution in volts. Resolution in volts = volts per step = 0.01V 0r 10mV.

Discussion

106.	The gates G and G in the figure have propagation delays of 10 n sec. and 20 n sec. respectively. If the input V makes an output change from logic 0 to 1 at time = then the output wavefrom V is
Answer» Truth table are as follows.

Discussion

107.	The maximum counting range of a four stage counter using IC 74193 is
Answer» IC 74193 is a divide by 16 counter. Since 4 stages are used, counting range = 164 = 65536.

Discussion

108.	The circuit of the given figure is
Answer»

Discussion

109.	A half adder adds
Answer»

Discussion

110.	The no. of comparators required in a 3 bit comparator type ADC is
Answer» Number of comparators = 2n - 1 = 23 - 1 = 7.

Discussion

111.	If the ladder reference voltage is 2 V, then minimum comparator resolution required is
Answer» .

Discussion

112.	In a 7 segment LED display, the minimum number of segments is activated when the input decimal number is
Answer» Only 2 segments are lit as seen in

Discussion

113.	The number of bits in EBCDIC is
Answer» EBCDIC is an 8 bit code.

Discussion

114.	A 3 bit up-down counter can count from
Answer» Since it is an up-down counter it can count upwards or downwards.

Discussion

115.	The density of dynamic RAM is
Answer» Dynamic RAM has higher packing density and requires lesser space.

Discussion

116.	To count 1000 bottles in a milk plant, the minimum number of flip flops requires is
Answer» 20 = 512 and 210 = 1024 Hence at least 10 flip-flops are required.

Discussion

117.	Decimal 8 in excess-3 code =
Answer» Decimal 8 in excess 3 code = decimal 11 = 1011 in binary.

Discussion

118.	The inputs to a 3 bit binary adder are 111 and 110. The output will be
Answer» Rules for binary addition. 0 + 0 = 0 0 + 1 = 1 + 0 = 1 1 + 1 = 10 i.e., 1 + 1 equals 0 with a carry of 1 to next higher column. 1 + 1 + 1 = 11 i.e., 1 + 1 + 1 equals 1 with a carry of 1 to next higher column.

Discussion

119.	BCD equivalent of - 8 is
Answer» Decimal 8 = 1000 and - 8 = 11000.

Discussion

120.	The number of inputs and outputs in a full adder are
Answer»

Discussion

121.	Logic hardware is available only in NAND and NOR.
Answer» Other gates are also available.

Discussion

122.	A 4 input AND gate is equivalent to
Answer» All the switches have to be closed so that the circuit can be made. In AND gate all the inputs have to be high for output to be high.

Discussion

123.	The function of interface circuit is
Answer» Output of driver stage has to be matched with input of load.

Discussion

124.	1274 - 3A7 = __________ .
Answer» Convert to decimal, subtract and change the result to hexadecimal.

Discussion

125.	The number of memory locations in which 14 address bits can access is
Answer» 214 = 16384.

Discussion

126.	A 6 bit R-2 ladder D/A converter has a reference voltage of 6.5 V. It meets standard linearity then resolution in percent and volts.
Answer» R-2R ladder, resolution = Resolution in volts = .

Discussion

127.	What will be output for decimal input 82?
Answer» Output for decimal input 82/(10000010) = 0.01 x 82 = 0.82 V.

Discussion

128.	The circuit of the given figure gives the output =
Answer» When any input is High, the corresponding transistor conducts and output is Low. Hence it is a NOR gate.

Discussion

129.	Two 2's complement number having sign bits X and Y are added and the sign bit of the result is Z. then, the occurrence of overflow is indicated by the Boolean function.
Answer» carry of a one bit full order is given by expression XY + YZ + ZX.

Discussion

130.	If A = 0101, then A' is
Answer» A' = 1010 + 1 = 1011.

Discussion

131.	A + A . B =
Answer» A.B= 1 or 0, A + A.B = 0 if A is zero and A + A.B = 1 if A = 1. Hence A + A.B = A.

Discussion

132.	The device 'one shot' has
Answer» One shot means one stable state.

Discussion

133.	For the logic circuit of the given figure the simplified Boolean expression is
Answer» #NAME?

Discussion

134.	If number of information bits is 4, the parity bits in Hamming code are located at bit positions __________ from the LSB.
Answer» The number of parity bits is 3. These bits are located at 20, 21, 22, i.e., 1, 2, 4th bits starting from LSB.

Discussion

135.	A certain JK FF has = 12 n sec the largest MOD counter that can be constructed from these FF and still operate up to 10 MHz is
Answer» Clock period(t) = = 10-7 sec Number of FF = mod counter 28 = 256.

Discussion

136.	11011 in gray code = __________ .
Answer» Change to decimal and then to binary.

Discussion

137.	In the circuit of the given figure, Y =
Answer» XX = 0.

Discussion

138.	A . 0 =
Answer» 1.0 = 0 and 0.0 = 0.

Discussion

139.	Decimal -90 equals __________ in 8 bit 2s complement
Answer» +90 in binary is 01011010. Its 2's complement is 10100110.

Discussion

140.	23.6 = __________
Answer» 23= 10111 and 0.6 =10011 Hence 10111 . 10011 .

Discussion

141.	In a shift left register, shifting a bit by one bit means
Answer» In binary shift one bit left means multiplication by 2.

Discussion

142.	If A = B = 1, the outputs P and Q in the given figure are
Answer» It is a half adder 1 + 1 = 10. Therefore SUM = P = 0 and Carry = Q = 1.

Discussion

143.	The complement of exclusive OR function is
Answer» Complement of XOR is X NOR.

Discussion

144.	In the given figure, Y =
Answer» .

Discussion

145.	In a 3 input NOR gate, the number of states in which output is 1 equals
Answer» Only one input, i.e., A = 0, B = 0 and C = 0 gives 1 as output.

Discussion

146.	The series 54 H/74 H denotes
Answer» It denotes high speed TTL.

Discussion

147.	For a 4096 x 8 EPROM, the number of address lines is
Answer» 4096 = 212 .

Discussion

148.	+ C =
Answer» A B C D + A B C D = A B D(C + C) = A B D .

Discussion

149.	Find the output voltage for 011100 in a 6 bit R-2 ladder D/A converter has a reference voltage of 6.5 V.
Answer» (an-1 2n-1 + an-2 2n-2 + .....a121 + a020) (24 + 23 + 22) = 6.5 x = 2.84 .

Discussion

150.	Binary number 1101 is equal to octal number
Answer» 1101 = 13 in decimal = 15 (i.e., 8 + 5) in octal.

Discussion

Explore topic-wise InterviewSolutions in .

What will be FSV in 2 bit BCD D/A converter is a weighted resistor type with E = 1V, R = 1 MΩ and R = 10KΩ

With four Boolean variables, how many Boolean expressions can be performed?

A + (B . C) =

The number of logic devices required in a Mod-16 synchronous counter are

A 2 bit BCD D/A converter is a weighted resistor type with E = 1V, R = 1 MΩ and R = 10KΩ then Resolution in percent and volt is __________ .

The gates G and G in the figure have propagation delays of 10 n sec. and 20 n sec. respectively. If the input V makes an output change from logic 0 to 1 at time = then the output wavefrom V is

The maximum counting range of a four stage counter using IC 74193 is

The circuit of the given figure is

A half adder adds

The no. of comparators required in a 3 bit comparator type ADC is

If the ladder reference voltage is 2 V, then minimum comparator resolution required is

In a 7 segment LED display, the minimum number of segments is activated when the input decimal number is

The number of bits in EBCDIC is

A 3 bit up-down counter can count from

The density of dynamic RAM is

To count 1000 bottles in a milk plant, the minimum number of flip flops requires is

Decimal 8 in excess-3 code =

The inputs to a 3 bit binary adder are 111 and 110. The output will be

BCD equivalent of - 8 is

The number of inputs and outputs in a full adder are

Logic hardware is available only in NAND and NOR.

A 4 input AND gate is equivalent to

The function of interface circuit is

1274 - 3A7 = __________ .

The number of memory locations in which 14 address bits can access is

A 6 bit R-2 ladder D/A converter has a reference voltage of 6.5 V. It meets standard linearity then resolution in percent and volts.

What will be output for decimal input 82?

The circuit of the given figure gives the output =

Two 2's complement number having sign bits X and Y are added and the sign bit of the result is Z. then, the occurrence of overflow is indicated by the Boolean function.

If A = 0101, then A' is

A + A . B =

The device 'one shot' has

For the logic circuit of the given figure the simplified Boolean expression is

If number of information bits is 4, the parity bits in Hamming code are located at bit positions __________ from the LSB.

A certain JK FF has = 12 n sec the largest MOD counter that can be constructed from these FF and still operate up to 10 MHz is

11011 in gray code = __________ .

In the circuit of the given figure, Y =

A . 0 =

Decimal -90 equals __________ in 8 bit 2s complement

23.6 = __________

In a shift left register, shifting a bit by one bit means

If A = B = 1, the outputs P and Q in the given figure are

The complement of exclusive OR function is

In the given figure, Y =

In a 3 input NOR gate, the number of states in which output is 1 equals

The series 54 H/74 H denotes

For a 4096 x 8 EPROM, the number of address lines is

+ C =

Find the output voltage for 011100 in a 6 bit R-2 ladder D/A converter has a reference voltage of 6.5 V.

Binary number 1101 is equal to octal number