Analog Electronics - 8 for GATE EE and Digital - Free MCQ Test with solutions

Analog Electronics - 8 - Question 1

Which is the frequency of the given 555 timer?

A.
900 H_Z
B.
1200 H_Z
C.
1800 H_Z
D.
720 H_Z

Detailed Solution: Question 1

The waveforms will be like

The charge of the capacitor varies between

When capacitor is getting charged, output V₀ is high

When capacitor is getting discharged, output V₀ is low

The time period of o/p, T = T_high+ T_low

In T_high,i.e. charging time, both R_A& R_B are in play.

In T_low, i.e. discharging time,

T_low, i.e. discharging time,

T_low = 0.693 R_BC

T = T_high + T_low

= 0. 693(R_A + 2R_B)C

= 0.693 (8 + (2 × 4) × 10³ × 0.1 × 10^-6)

= 0.693 × 16 × 10³ × 10^-7

*Answer can only contain numeric values

Analog Electronics - 8 - Question 2

In the above monostable multivibrator circuit above given C = 10 nF. If the frequency of output pulse is 100 kHz the resistor value is _________ kΩ

Detailed Solution: Question 2

The pulse duration in mono-stable multivibrator using 555 timer is T = RC In3

10^-5 = 1.1 × R × 10 × 10^-9

R = 909.1 Ω

≃ 0.91 kΩ

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Analog Electronics - 8 - Question 3

For the 555 timer circuit, if R_A = R_B then

A.
Duty cycle is 50% irrespective of R_A = R_B values
B.
The output cycle is not affected by R_A & R_B
C.
The duty cycle of the output is greater than 50%
D.
The duty cycle of the output is less than 50%

Detailed Solution: Question 3

The ON time of 555 timer is T_ON = R_A + R_B and OFF time T_OFF = R_B

≃ 66% > 50%

Analog Electronics - 8 - Question 4

A dc voltage of 380 V with a peak ripple voltage not exceeding 7 V is required to supply a 500 Ω load. Find out the inductance required.

A.
10.8 Henry
B.
30.7 Henry
C.
28.8 Henry
D.
15.4 Henry

Detailed Solution: Question 4

We know that the ripple factor

Where r = RMS value of AC component/DC component

RMS value of AC component = 7/1.414 = 4.95

L = 28.8 H

*Answer can only contain numeric values

Analog Electronics - 8 - Question 5

A shunt regular is shown in the figure has a regulated output voltage of 10 V. Given V_z = 9.3, V_BE = 0 .7 V, β = 49. Neglecting the current through Resistor R_B the ratio of maximum power dissipated in the transistor to the maximum power dissipated in the Zener diode is ________

Detailed Solution: Question 5

Maximum input current

The Base current is equal to current flowing through Zener diode

V_z = I_B

→ I_c = βI_B = βI_Z

I₁ = βI_Z + I_z

1A = (49 + 1) I_z

I_z = 20 mA

∴ Power dissipated by the Zener diode P_z = V_zI_z

= 9.3 × 0.02 = 186 mW

Power dissipated by the Zener diode P_c = I_c × V_c

I_C = 99I_z; V_C = V_O

⇒ P_C = 0.98 × 10 = 9.8 W
∴ The ratio =

Analog Electronics - 8 - Question 6

For the circuit shown, the value of C = 1 nF, the value of R_A & R_B such that oscillation frequency of 100 kHz and duty cycle frequency of 75% is obtained at the output is

A.
3.6 k, 7.2 k
B.
7.2 k, 3.6 k
C.
2.4 k, 4.8 k
D.
4.8 k, 2.4 k

Detailed Solution: Question 6

T = 0.69 C (R_A + 2R_B)

4R_B = 14452.75

R_B = 3623

3.6 K

R_A = 7.2 K

*Answer can only contain numeric values

Analog Electronics - 8 - Question 7

The frequency of oscillation of the astable multivibrator circuit given below is ______

Detailed Solution: Question 7

The time period of astable multivibrator given is

T = 0.693 (R_A + 2R_B) C

Where R_A = 9.5 kΩ R_B = 7.5 kΩ

C = 0.1 μF

Frequency of oscillation is given by F = 1/T

Analog Electronics - 8 - Question 8

For the given circuit, what is the value of power dissipated in zener diode ?

A.
238.6 mW
B.
477.28 mW
C.
160 mW
D.
320 mW

Detailed Solution: Question 8

The given circuit is of a voltage regulator, hence the output voltage will remain fixed due to zener diode.
V₀ = V_Z – V_BE = 12 − 0.7 = 11.3V
V_CE = 20 – 11.3 = 8.7V

Hence power dissipated in zener diode is P_dis= V_Z× I = 477.3 mW

*Answer can only contain numeric values

Analog Electronics - 8 - Question 9

The output voltage of the voltage regulator is constant at 18.5 V. Assuming the op-amp and Zener diode are ideal, the maximum power dissipated in the transistor is ______ mw. The transistor β is very high.

Detailed Solution: Question 9

Due to virtual short, the voltage at inverting terminal is V_z
Then the current

≃ 0.545 mA

Since op-amp is ideal no current is drawn by it,

⇒ I_C ≃ I_E = I₁

V_CE = (20 ~ 40) V – 18.5 V

V_CEmax = 21.5 V

Power dissipated (maximum) = 21.5 × 0.545 mA

≃ 11.72 mW

*Answer can only contain numeric values

Analog Electronics - 8 - Question 10

For the timer circuit shown below the frequency of oscillation is __________ kHz.

Detailed Solution: Question 10

In the given circuit R_A= 10 kΩ R_B = 5 kΩ C = 1 nF

The frequency of oscillation

Normally the duration of 'high' of pulse is T_H = C(R_A + R_B)ln 2, but the diode bypasses the lower resistance R_B. And the capacitor is charged only through R_A.

Hence T_H is = 0.69R_AC and T_L = 0.69R_BC

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Analog Electronics - 8 - Free MCQ Test with solutions for GATE EE and Digital

MCQ Practice Test & Solutions: Analog Electronics - 8 (10 Questions)

Which is the frequency of the given 555 timer?

In the above monostable multivibrator circuit above given C = 10 nF. If the frequency of output pulse is 100 kHz the resistor value is _________ kΩ

For the 555 timer circuit, if R_A = R_B then

A dc voltage of 380 V with a peak ripple voltage not exceeding 7 V is required to supply a 500 Ω load. Find out the inductance required.

A shunt regular is shown in the figure has a regulated output voltage of 10 V. Given V_z = 9.3, V_BE = 0 .7 V, β = 49. Neglecting the current through Resistor R_B the ratio of maximum power dissipated in the transistor to the maximum power dissipated in the Zener diode is ________

For the circuit shown, the value of C = 1 nF, the value of R_A & R_B such that oscillation frequency of 100 kHz and duty cycle frequency of 75% is obtained at the output is

The frequency of oscillation of the astable multivibrator circuit given below is ______

For the given circuit, what is the value of power dissipated in zener diode ?

The output voltage of the voltage regulator is constant at 18.5 V. Assuming the op-amp and Zener diode are ideal, the maximum power dissipated in the transistor is ______ mw. The transistor β is very high.

For the timer circuit shown below the frequency of oscillation is __________ kHz.

Analog and Digital Electronics

Analog and Digital Electronics

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Analog Electronics - 8 - Free MCQ Test with solutions for GATE EE and Digital

MCQ Practice Test & Solutions: Analog Electronics - 8 (10 Questions)

Which is the frequency of the given 555 timer?

In the above monostable multivibrator circuit above given C = 10 nF. If the frequency of output pulse is 100 kHz the resistor value is _________ kΩ

For the 555 timer circuit, if RA = RB then

A dc voltage of 380 V with a peak ripple voltage not exceeding 7 V is required to supply a 500 Ω load. Find out the inductance required.

A shunt regular is shown in the figure has a regulated output voltage of 10 V. Given Vz = 9.3, VBE = 0 .7 V, β = 49. Neglecting the current through Resistor RB the ratio of maximum power dissipated in the transistor to the maximum power dissipated in the Zener diode is ________

For the circuit shown, the value of C = 1 nF, the value of RA & RB­ such that oscillation frequency of 100 kHz and duty cycle frequency of 75% is obtained at the output is

The frequency of oscillation of the astable multivibrator circuit given below is ______

For the given circuit, what is the value of power dissipated in zener diode ?

The output voltage of the voltage regulator is constant at 18.5 V. Assuming the op-amp and Zener diode are ideal, the maximum power dissipated in the transistor is ______ mw. The transistor β is very high.

For the timer circuit shown below the frequency of oscillation is __________ kHz.

Analog and Digital Electronics

Analog and Digital Electronics

Top Courses for Electrical Engineering (EE)

About this Electrical Engineering (EE) Practice Test

Explore more Electrical Engineering (EE) Study Resources

For the 555 timer circuit, if R_A = R_B then

A shunt regular is shown in the figure has a regulated output voltage of 10 V. Given V_z = 9.3, V_BE = 0 .7 V, β = 49. Neglecting the current through Resistor R_B the ratio of maximum power dissipated in the transistor to the maximum power dissipated in the Zener diode is ________

For the circuit shown, the value of C = 1 nF, the value of R_A & R_B such that oscillation frequency of 100 kHz and duty cycle frequency of 75% is obtained at the output is