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Electrical Circuits(23)Electrical Machines(6)

Electrical Circuits

23 Questions

GATE→2026→Electrical Circuits and Machines→Electrical Circuits

Q1

MCQ[1 Mark]

The RLC filter shown below acts as a

(A)

low pass filter

(B)

high pass filter

(C)

band pass filter

(D)

band stop filter

Explanation

GATE→2026→Electrical Circuits and Machines→Electrical Circuits

Q2

MCQ[1 Mark]

A single phase step-down transformer has a high voltage primary winding and a low voltage secondary winding. The secondary winding is connected to a load impedance $Z_{2}$. The impedance $Z_{2}$ when referred to the primary winding is denoted by $Z_{2}'$. Which of the following conditions is true?

(A)

$Z_{2}' = Z_{2}$

(B)

$0.5 Z_{2} < Z_{2}' < Z_{2}$

(C)

$Z_{2}' > Z_{2}$

(D)

$Z_{2}' \le 0.5 Z_{2}$

Explanation

GATE→2026→Electrical Circuits and Machines→Electrical Circuits

Q3

NAT[1 Mark]

In a series RL circuit shown in the figure, the current through the resistor lags the AC source voltage by $45^{\circ}$. Let $R = 100\pi$ \Omega and $L = 2$ H. The frequency of the source is Hz. (rounded off to the nearest integer)

Explanation

GATE→2026→Electrical Circuits and Machines→Electrical Circuits

Q4

NAT[1 Mark]

In the circuit below the maximum value of $v_{out}$ is V. (rounded off to the nearest integer)

Explanation

GATE→2026→Electrical Circuits and Machines→Electrical Circuits

Q5

MCQ[2 Marks]

A two-port network has z-parameters $z_{11} = z_{22} = 10$ \Omega, and $z_{12} = z_{21} = 5$ \Omega. The value of $R_{L}$ such that maximum power is transferred to $R_{L}$ is \Omega.

(A)

5.67

(B)

8.33

(C)

10.33

(D)

25.67

Explanation

GATE→2026→Electrical Circuits and Machines→Electrical Circuits

Q6

MCQ[2 Marks]

In the circuit shown below, the value of the output voltage $V_{0}$ is V.

(A)

2

(B)

3

(C)

4

(D)

8

Explanation

GATE→2025→Electrical Circuits and Machines→Electrical Circuits

Q7

MCQ[1 Mark]

The circuit shown in Figure (a) can be represented using its equivalent T-model as shown in Figure (b). The values of the inductances $L_{1}, L_{2}$, and $L_{3}$ in the equivalent T-model are

(A)

$L_{1} = 7$ H, $L_{2} = 6$ H, $L_{3} = -4$ H

(B)

$L_{1} = -1$ H, $L_{2} = -2$ H, $L_{3} = 4$ H

(C)

$L_{1} = 3$ H, $L_{2} = 2$ H, $L_{3} = 9$ H

(D)

$L_{1} = 1$ H, $L_{2} = -2$ H, $L_{3} = -4$ H

Explanation

GATE→2025→Electrical Circuits and Machines→Electrical Circuits

Q8

MCQ[1 Mark]

Three parallel admittances $Y_{a} = -j0.2$ S, $Y_{b} = 0.3$ S, and $Y_{c} = j0.4$ S connected in parallel with a voltage source $V_{s} = 10 \angle 45^{\circ}$ V, draw a total current $I_{s}$ from the source. The currents flowing through each of these admittances are $I_{a}, I_{b}$ and $I_{c}$ respectively. Let $I = I_{b} + I_{c}$. The phase relation between I and $I_{s}$ is

(A)

I leads $I_{s}$ by $19.44^{\circ}$

(B)

I lags $I_{s}$ by $19.44^{\circ}$

(C)

I leads $I_{s}$ by $33.69^{\circ}$

(D)

I lags $I_{s}$ by $33.69^{\circ}$

Explanation

GATE→2025→Electrical Circuits and Machines→Electrical Circuits

Q9

NAT[2 Marks]

The circuit given in the figure is driven by a voltage source $V_{s} = 25\sqrt{2} \angle 30^{\circ}$ V... The average power dissipated, in W, in the 50 k\Omega resistance is (rounded off to two decimal places).

Explanation

GATE→2025→Electrical Circuits and Machines→Electrical Circuits

Q10

NAT[2 Marks]

In the circuit shown, the switch is opened at $t = 0$ s. The current $i(t)$ at $t = 2$ ms is mA (rounded off to two decimal places).

Explanation

GATE→2025→Electrical Circuits and Machines→Electrical Circuits

Q11

NAT[2 Marks]

For the circuit shown in the figure, the active power supplied by the source is W (rounded off to one decimal place).

Explanation

GATE→2024→Electrical Circuits and Machines→Electrical Circuits

Q12

NAT[1 Mark]

The switch in the following figure has been closed for a long time ($t < 0$). It is opened at $t = 0$ seconds. The value of $dv_{c}/dt$ at $t = 0^{+}$ is V/s (rounded off to nearest integer).

Explanation

GATE→2024→Electrical Circuits and Machines→Electrical Circuits

Q13

NAT[2 Marks]

In the circuit shown, assume the opamp is ideal and the initial charge on the capacitor is zero. The output voltage at time $t = 2$ ms is V (rounded off to one decimal place).

Explanation

GATE→2024→Electrical Circuits and Machines→Electrical Circuits

Q14

NAT[2 Marks]

Two magnetically coupled coils, when connected in series-aiding configuration, have a total inductance of 500 mH. When connected in series-opposing configuration, the coils have a total inductance of 300 mH. If the self-inductance of both the coils are equal, then the coupling coefficient is (rounded off to two decimal places).

Explanation

GATE→2023→Electrical Circuits and Machines→Electrical Circuits

Q15

NAT[1 Mark]

In the circuit given, the Thevenin equivalent resistance $R_{th}$ across the terminals 'a' and 'b' is \Omega (rounded off to one decimal place).

Explanation

GATE→2023→Electrical Circuits and Machines→Electrical Circuits

Q16

NAT[2 Marks]

In the circuit shown, $\omega = 100\pi$ rad/s, $R_{1} = R_{2} = 2.2$ \Omega and $L = 7$ mH. The capacitance C for which $Y_{in}$ is purely real is mF (rounded off to two decimal places).

Explanation

GATE→2023→Electrical Circuits and Machines→Electrical Circuits

Q17

NAT[2 Marks]

The R-L circuit with $R = 10$ k\Omega and $L = 1$ mH is excited by a step current $I_{0}u(t)$... The minimum time taken for the current through the inductor to reach 99% of its final value is \mu\text{s} (rounded off to two decimal places).

Explanation

GATE→2023→Electrical Circuits and Machines→Electrical Circuits

Q18

NAT[2 Marks]

A sinusoidal current of $i_{1}(t) = 1 \sin(200\pi t)$ mA is flowing through a 4 H inductor... The peak energy stored in the circuit is \mu\text{J} (rounded off to two decimal places).

Explanation

GATE→2023→Electrical Circuits and Machines→Electrical Circuits

Q19

NAT[2 Marks]

The voltage source $V_{s} = 10\sqrt{2}\sin(20000\pi t)$ V has an internal resistance of 50 \Omega. The RMS value of the current through R is mA (rounded off to one decimal place).

Explanation

GATE→2022→Electrical Circuits and Machines→Electrical Circuits

Q20

NAT[1 Mark]

In the bandpass filter circuit shown, $R_{0} = 50$ \Omega, $L_{0} = 1$ mH, $C_{0} = 10$ nF. The Q factor of the filter is (round off to two decimal places).

Explanation

GATE→2022→Electrical Circuits and Machines→Electrical Circuits

Q21

NAT[2 Marks]

In the circuit shown, the load is driven by a sinusoidal ac voltage source... the power factor is (round off to one decimal place).

Explanation

GATE→2022→Electrical Circuits and Machines→Electrical Circuits

Q22

NAT[2 Marks]

Given Circuit A with currents $I_{1}$ and $I_{2}$ as shown, the current $I_{3}$ in Circuit B (in amperes), is (round off to one decimal place).

Explanation

GATE→2022→Electrical Circuits and Machines→Electrical Circuits

Q23

NAT[2 Marks]

In the circuit shown, the capacitance $C_{0} = 10$ \mu\text{F} and inductance $L_{0} = 1$ mH and the diode is ideal... the voltage $V_{c}(t)$ (in volts) across the capacitor at $t = 0.5$ s is (round off to one decimal place).

Explanation

Electrical Machines

6 Questions

GATE→2026→Electrical Circuits and Machines→Electrical Machines

Q24

NAT[2 Marks]

A single phase transformer has a rating of 10 kVA, 50 Hz, 1100 V/220 V. In an open circuit test with the high voltage side open, the following are obtained: Voltage applied to the low voltage winding = 220 V, Measured power = 363 W, Measured current = 2.75 A. Magnetizing reactance $X_{m}$ referred to the high voltage winding is \Omega. (rounded off to the nearest integer)

Explanation

GATE→2025→Electrical Circuits and Machines→Electrical Machines

Q25

MCQ[2 Marks]

A 2-pole, 50 Hz, 3-phase induction motor supplies power to a certain load at 2970 rpm. The torque-speed curve of this machine follows a linear relationship between synchronous speed and 95% of synchronous speed. Assume mechanical and stray losses to be zero. If the load torque of the motor is doubled, the new operating speed of the motor, in rpm, is

(A)

2940

(B)

2812

(C)

2970

(D)

2850

Explanation

GATE→2024→Electrical Circuits and Machines→Electrical Machines

Q26

NAT[2 Marks]

A 50 kVA transformer has an efficiency of 95% at full load and unity power factor. Assume the core losses are negligible. The efficiency of the transformer at 75% of the full load and 0.8 power factor is % (rounded off to one decimal place).

Explanation

GATE→2024→Electrical Circuits and Machines→Electrical Machines

Q27

NAT[2 Marks]

A three-phase squirrel-cage induction motor has a starting torque of 100% of the full load torque and a maximum torque of 300% of the full load torque. Neglecting the stator impedance, the slip at the maximum torque is % (rounded off to two decimal places).

Explanation

GATE→2023→Electrical Circuits and Machines→Electrical Machines

Q28

NAT[1 Mark]

The no-load steady-state output voltage of a DC shunt generator is 200 V when it is driven in the clockwise direction at its rated speed. If the same machine is driven at the rated speed but in the opposite direction, the steady-state output voltage will be V (rounded off to the nearest integer).

Explanation

GATE→2022→Electrical Circuits and Machines→Electrical Machines

Q29

NAT[1 Mark]

A 440 V, 8 kW, 4-pole, 50 Hz, star-connected induction motor has a full load slip of 0.04. The rotor speed (in rpm) at full load is (round off to one decimal place).

Explanation