Recent questions tagged electrical-circuits-and-machines

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}...

In the circuit shown, the BJT has a $\beta$ of $100$. The base-emitter junction voltage is $0.65$ $\mathrm{V}$. The quiescent collector current, $I_{C}$ is $\_\_\_\_$ $\m...

In a series $R L$ circuit shown in the figure, the current through the resistor lags the AC source voltage by $45^{\circ}$. Let $R=100 \pi \Omega$ and $L=2 \mathrm{H}$.Th...

A two-port network has $\mathrm{z}$-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_{...

In the circuit shown below, the value of the output voltage $V_{0}$ is $\_\_\_\_$ $\mathrm{V}$.$2$$3$$4$$8$

A single phase transformer has a rating of $10 \mathrm{kVA}, 50 \mathrm{~Hz}, 1100 \mathrm{~V} / 220 \mathrm{~V}$. In an open circuit test with the high voltage side open...

The working of the hand-held metal detector most widely used by security personnel for human frisking is based on the principle ofchange in reluctance of an iron core in ...

In a single-phase AC circuit, the power consumed by load resistance $R_{\mathrm{L}}$ for an excitation $V_{\mathrm{S}}$ is measured using a wattmeter. The same wattmeter ...

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 e...

Three parallel admittances $Y_{a}=-j 0.2 \mathrm{~S}, Y_{b}=0.3 \mathrm{~S}$, and $\quad Y_{c}=j 0.4 \mathrm{~S}$ connected in parallel with a voltage source $V_{s}=10 \a...

Power consumed by a three-phase balanced load is measured using two-wattmeter method. The per-phase average power drawn by the load is $30 \: \mathrm{kW}$ at $\frac{\sqr...

The bridge circuit, shown in Figure (a), can be equivalently represented using the circuit shown in Figure (b). The values of $R_{1}, R_{2}$, and $V_{\mathrm{C}}$ in the ...

A $2$-pole, $50 \mathrm{~Hz}, 3$-phase induction motor supplies power to a certain load at $2970 \: \mathrm{rpm}$ . The torque-speed curve of this machine follows a linea...

A metallic strain-gauge $(\mathrm{SG})$ with resistance $R_{\mathrm{SG}}$ is connected as shown in the figure, where $R_{\mathrm{L} 1}, R_{\mathrm{L} 2}, R_{\mathrm{L} 3}...

Consider an AC bridge shown in the figure with $\mathrm{R}=300 \: \Omega, \mathrm{R} 1=1000 \: \Omega$, $\mathrm{R} 2=500 \: \Omega, \mathrm{~L}=30 \mathrm{mH}$, and a de...

An air filled parallel plate electrostatic actuator is shown in the figure. The area of each capacitor plate is $100 \: \mu \mathrm{m} \times 100 \: \mu \mathrm{m}$. The ...

The circuit given in the figure is driven by a voltage source $V_{S}=25 \sqrt{2} \angle 30^{\circ} \: \mathrm{V}$. The system is operating at a frequency of $50 \: \mathr...

In the circuit shown, the galvanometer $(G)$ has an internal resistance of $100 \: \Omega$. The galvanometer current $I_{G}$ is ____________ $\mu \mathrm{A}$ (rounded off...

A series RLC circuit resonates at $7500 \: \mathrm{rad} / \mathrm{s}$ for inductance $L=20 \: \mathrm{mH}$ and resistance $R=10\: \Omega$. The uncertainties in the measur...

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

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

The capacitance formed between two concentric spherical metal shells having radii $x$ and $y$ with $y>x$ isNote: $\epsilon$ is the permittivity of the medium between the ...

The voltage applied and the current drawn by a circuit are$$ \begin{array}{c} v(t)=95+200 \cos (120 \pi t)+90 \cos \left(360 \pi t-60^{\circ}\right) \mathrm{V} \\i(t)=4 \...

The current $i(t)$ drawn by a circuit is given as$$i(t)=4+30 \cos (t)-20 \sin (t)+15 \cos (3 t)-10 \sin (3 t) \mathrm{A}$$The root-mean-square value of $i(t)$ is $\_\_\_\...

A linear potentiometer $(0-10 \mathrm{k} \Omega)$ is used to measure the water level as shown in the figure. The resistance between $\mathrm{A}$ and $\mathrm{C}$ varies l...

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 $d v_{0} / d t$ at $t=0^{+}$is $\_\_\_\_\_\_ ~ \ma...

​A wire of circular cross section with radius $a$ is shown in the figure. The current density is given by $\mathbf{J}=k s^{2}$, where $k$ is a constant, $s$ is the radial...

​​​In the figure shown, assume$\alpha$ is the phase angle between the load current and the load voltage$\beta$ is the phase angle by which pressure coil current lags the ...

In the figure shown, $\mathrm{R}=4.5 \mathrm{~k} \Omega, \Delta \mathrm{R}=1.5 \mathrm{~k} \Omega$, and $\mathrm{INA}$ is assumed to be ideal. The equivalent resistance b...

A $50 \mathrm{~kVA}$ transformer has an efficiency of $95 \%$ at full load and unity power factor. Assume the core losses are negligible. The efficiency of the transforme...

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...

Two magnetically coupled coils, when connected in series-aiding configuration, have a total inductance of $500 \mathrm{~mH}$. When connected in series-opposing configurat...

Inductance of a coil is measured as $10 ~ \mathrm{mH}$, using an LCR meter, when no other objects are present near the coil. The LCR meter uses a sinusoidal excitation at...

Capacitance ' $\text{C}$ ' of a parallel plate structure is calculated as $20 ~ \mathrm{pF}$ using $C=\frac{\varepsilon_0 \varepsilon_r A}{d}$, where $\varepsilon_o$ is t...

The force per unit length between two infinitely long parallel conductors, with a gap of $2 \mathrm{~cm} $ between them is $10~ \mu \mathrm{N} / \mathrm{m}.$ When the gap...

When the bridge given below is balanced, the current through the resistor $\mathrm{R}_{\mathrm{a}}$ is____________ $\mathrm{mA}$ (rounded off to two decimal places).

In the circuit given, the Thevenin equivalent resistance $\mathrm{R}_{\mathrm{th}}$ across the terminals '$\mathrm{a}$' and ' $\mathrm{b}$' is____________$\Omega$ (rounde...

The full-scale range of the wattmeter shown in the circuit is $100 \mathrm{~W}$. The turns ratio of the individual transformers are indicated in the figure. The RMS value...

The no-load steady-state output voltage of a $\text{DC}$ shunt generator is $200 \mathrm{~V}$ when it is driven in the clockwise direction at its rated speed. If the same...