Questions & Answers of Analog and Digital Electronics

Question No. 20

A temperature in the range of −40° C to 55° C is to be measured with a resolution of 0.1° C. The minimum number of ADC bits required to get a matching dynamic range of the temperature sensor is

Question No. 21

Consider the following circuit which uses a 2-to-1 multiplexer as shown in the figure below. The Boolean expression for output F in terms of A and B is 


Question No. 22

A transistor circuit is given below. The Zener diode breakdown voltage is 5.3 V as shown. Take base to emitter voltage drop to be 0.6 V. The value of the current gain β is _________.


Question No. 46

The current state QA QB of a two JK flip-flop system is 00. Assume that the clock rise-time is much smaller than the delay of the JK flip-flop. The next state of the system is

Question No. 47

A 2-bit flash Analog to Digital Converter (ADC) is given below. The input is 0 ≤ VIN ≤ 3 Volts.The expression for the LSB of the output B0 as a Boolean function of X2, X1, and X0 is


Question No. 111

The output expression for the Karnaugh map shown below is

Question No. 112

The circuit shown below is an example of a


Question No. 136

The Boolean expression $\overline{\left(a+\overline b+c+\overline d\right)+\left(b+\overline c\right)}$ simplifies to

Question No. 137

For the circuit shown below, taking the opamp as ideal, the output voltage Vout in terms of the input voltages V1 , V2 and V3 is


Question No. 17

Of the four characteristic given below, which are the major requirements for an instrumentation amplifier?
P. High common mode rejection ratio
Q. High input impedance
R. High linearity
S. High output impedance

Question No. 23

Consider the circuit shown in the figure,. In this circuit R = 1kΩ, and C=1μF. The input voltage is sinusoidal with a frequency of 50 Hz, represented as phasor with magnitude Vi and phase angle 0 radian as shown in the figure. The output voltage is represented as a phasor with magnitude V0 and phase angle δ radian. What is the value of the output phase angle δ (in radian) relative to the phase angle of the input voltage?

Question No. 24

In the given circuit, the silicon transistor has β=75  and collector voltage Vc=9V .  Then the ratio of RB and RC is _______.

Question No. 47

The figure shows a digital circuit constructed using negative edge triggered J-K flip flops. Assume a starting state of Q2Q1Q0=000. This state Q2Q1Q0=000 will repeat after ________ number of cycles of the clock CLK.

Question No. 48

f(A,B,C,D) = ΠM (0,1,3,4,5,7,9,11,12,13,14,15) is a maxterm representation of a Boolean function f(A,B,C,D) where A is the MSB and D is the LSB. The equivalent minimized representation of this function is

Question No. 49

The op-amp shown in the figure has a finite gain A = 1000 and an infinite input resistance. A step-voltage Vi= 1 mV is applied at the input at time t = 0 as shown. Assuming that the operational amplifier is not saturated, the time constant (in millisecond) of the output voltage V0 is

Question No. 50

An 8 bit unipolar Successive Approximation Register type ADC is used to convert 3.5 V to digital equal output. The reference voltage is +5 V. The output of ADC at end of 3rd clock pulse after the start of conversion is ________.

Question No. 121

The operational amplifier shown in the figure is ideal. The input voltage (in Volt) is V1= 2sin2π×2000t. The amplitude of the output voltage V0 (in Volt) is ________.

Question No. 122

In the following circuit, the transistor is in active mode and Vc = 2V. To get Vc= 2V. To get Vc= 4V, we replace Rc with R'c . Then the ratio R'c/Rc is _________.

Question No. 123

Consider the following Sum of Products expression,,F.
The equivalent Product of Sums expression is

Question No. 124

The filters F1 and F2 having characteristics as shown in Figures (a) and (b) are connected as shown in Figure (c).

The cut-off frequencies of F1 and F2 are f1 and f2 respectively. If f1< f2, the resultant circuit exhibits the characteristics of a

Question No. 125

When a bipolar junction transistor is operating in the saturation mode, which one of the following statement is TRUE about the state of its collector-base (CB) and the baseemitter (BE) junctions?

Question No. 147

In the following sequential circuit, the initial state (before the first clock pulse ) of the circuit is Q1Q0= 00. The state (Q1Q0), immediately after the 333rd clock pulse is

Question No. 148

A Boolean funcation f(A, B, C, D) = Π(1, 5, 12, 15) is to be implemented using an 8×1 multiplexer (A is MSB). The inputs ABC are connected to the select inputs S2S1S0 of the multiplexer respectively.

Which one of the following options gives the correct inputs to pins 0,1,2,3,4,5,6,7 in order?

Question No. 149

The saturation voltage of the ideal op-amp shown below is ±10 V. The output voltage v0 of the following circuit in the steady-state is

Question No. 31

A cascade of three identical modulo-5 counters has an overall modulus of

Question No. 32

In the Wien Bridge oscillator circuit shown in figure, the bridge is balanced when

Question No. 33

The magnitude of the mid-band voltage gain of the circuit shown in figure is (assuming hfe of the transistor to be 100)

Question No. 59

Given that the op-amps in the figure are ideal, the output voltage V0 is

Question No. 60

Which of the following logic circuits is a realization of the function F whose Karnaugh map is shown in figure

Question No. 61

In the figure shown, assume the op-amp to be ideal. Which of the alternatives gives the correct Bode plots for the transfer function V0ωViω ?

Question No. 62

An output device is interfaced with 8-bit microprocessor 8085A. The interfacing circuit is shown in figure

The interfacing circuit makes use of 3 Line to 8 Line decoder having 3 enable lines E1 , E¯2 , E¯3 . The address of the device is

Question No. 131

Which of the following is an invalid state in an 8-4-2-1 Binary Coded Decimal counter

Question No. 132

The transistor in the given circuit should always be in active region. Take VCE(sat) =0.2 V, VBE =0.7 V. The maximum value of RC in Ω which can be used, is ______________.

Question No. 133

The sinusoidal ac source in the figure has an rms value of 202  V. Considering all possible values of RL, the minimum value of RS in Ω to avoid burnout of the Zener diode is _________.

Question No. 139

Assuming the diodes to be ideal in the figure, for the output to be clipped, the input voltage vi must be outside the range

Question No. 145

A 10 kHz even-symmetric square wave is passed through a bandpass filter with centre frequency at 30 kHz and 3 dB passband of 6 kHz. The filter output is

Question No. 159

An oscillator circuit using ideal op-amp and diodes is shown in the figure.

The time duration for +ve part of the cycle is Δt1 and for –ve part is Δt2. The value of Δt1-Δt2RC will be _____________.

Question No. 160

The SOP (sum of products) form of a Boolean function is 0,1,3,7,11,, where inputs are A,B,C,D (A is MSB, and D is LSB). The equivalent minimized expression of the function is

Question No. 161

A JK flip flop can be implemented by T flip-flops. Identify the correct implementation.

Question No. 162

In an 8085 microprocessor, the following program is executed

Address location – Instruction

2000H XRA  A
2001H MVI B,04H
2003H MVI A, 03H
2005H RAR
2006H DCR B
2007H JNZ 2005

At the end of program, register A contains

Question No. 231

A state diagram of a logic gate which exhibits a delay in the output is shown in the figure, where X is the don’t care condition, and Q is the output representing the state.

The logic gate represented by the state diagram is

Question No. 232

An operational-amplifier circuit is shown in the figure.

The output of the circuit for a given input vi is

Question No. 233

In 8085A microprocessor, the operation performed by the instruction LHLD 2100H is

Question No. 259

Two monoshot multivibrators, one positive edge triggered (M1) and another negative edge triggered (M2), are connected as shown in figure

The monoshots M1 and M2 when triggered produce pulses of width T1 and T2 respectively, where T1>T2. The steady state output voltage vo of the circuit is

Question No. 260

The transfer characteristic of the Op-amp circuit shown in figure is

Question No. 261

A 3-bit gray counter is used to control the output of the multiplexer as shown in the figure. The initial state of the counter is 0002. The output is pulled high. The output of the circuit follows the sequence

Question No. 262

A hysteresis type TTL inverter is used to realize an oscillator in the circuit shown in the figure.

If the lower and upper trigger level voltages are 0.9 V and 1.7 V, the period (in ms), for which output is LOW, is __________.

Question No. 1

In the circuit shown below what is the output voltage (Vout) in Volts if a silicon transistor Q and an ideal op-amp are used?

Question No. 13

In the feedback network shown below, if the feedback factor k is increased, then the

Question No. 27

In the circuit shown below, the knee current of the ideal Zener diode is 10 mA. To maintain 5 V across RL, the minimum value of RL in Ω and the minimum power rating of the Zener diode in mW respectively are

Question No. 31

A voltage 1000sinωt Volts is applied across YZ. Assuming ideal diodes, the voltage measured across WX in Volts is

Question No. 37

The clock frequency applied to the digital circuit shown in the figure below is 1 kHz. If the initial state of the output Q of the flip-flop is ‘0’, then the frequency of the output waveform Q in kHz is

Question No. 38

In the circuit shown below, Q1 has negligible collector-to-emitter saturation voltage and the diode drops negligible voltage across it under forward bias. If Vcc is +5 V, X and Y are digital signals with 0 V as logic 0 and Vcc as logic 1, then the Boolean expression for Z is

Question No. 39

In the circuit shown below the op-amps are ideal. Then Vout in Volts is

Question No. 7

In the sum of products function f(X,Y,Z)=2,3,4,5,the prime implicants are

Question No. 18

The i-v characteristics of the diode in the circuit given below are

The current in the circuit is