Recent questions tagged electrical-circuits-and-machines

In the circuit shown, $\omega=100 \pi \mathrm{rad} / \mathrm{s}, \mathrm{R}_1=\mathrm{R}_2=2.2 \Omega$ and $\mathrm{L}=7 \mathrm{mH}$. The capacitance $C$ for which $Y_{\...

The $\mathrm{R}-\mathrm{L}$ circuit with $\mathrm{R}=10 ~ \mathrm{k} \Omega$ and $\mathrm{L}=1 \mathrm{mH}$ is excited by a step current $\mathrm{I}_{\mathrm{u}} \mathrm{...

A sinusoidal current of $i_1(t)=1 \sin (200 \pi t) \mathrm{mA}$ is flowing through a $4~ \mathrm{H}$ inductor which is mutually coupled to another $5 ~ \mathrm{H}$ induct...

A short-circuit test is conducted on a single-phase transformer by shorting its secondary. The frequency of input voltage is $1 ~ \mathrm{kHz}$. The corresponding wattmet...

The voltage source $\mathrm{Vs}=10 \sqrt{2} \sin (20000 \pi t) ~ \mathrm{V}$ has an internal resistance of $50~ \Omega$. The RMS value of the current through $\mathrm{R}$...

The resistance of a pure copper wire of length $10 \; \text{cm}$ and diameter $1 \; \text{mm}$ is to be measured. The most suitable method from amongst the choices given ...

A $\text{440 V, 8 kW, 4-pole, 50 Hz,}$ 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 ...

In the circuit shown, the load is driven by a sinusoidal ac voltage source $V_{1} =100 \; \angle 0^{\circ} \; \text{V}$ at $50 \; \text{Hz}.$ Given $R_{1}=20 \; \Omega, ...

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

In the balanced three-phase circuit shown, $C_{0} = 8.2 \; \mu \text{F}$ and the line-to-line $\text{r.m.s.}$ voltage is $440 \; \text{V}$ at $50 \; \text{Hz}.$ The readi...

A conducting semi-circular loop of radius $R=0.1 \; \text{m}, $ with its diameter centered at the origin, rotates in the $x-y$ plane about the origin with a constant angu...

In the circuit shown, the capacitance $C_{0}=10 \; \mu \text{F}$ and inductance $\text{L}_{0} = 1 \; \text{mH}$ and the diode is ideal. The capacitor is initially charged...

A single-phase transformer has a magnetizing inductance of $\text{250 mH}$ and a core loss resistance of $300\: \Omega$, referred to primary side. When excited with a $\t...

A $\text{300 V}$, $\text{5 A}$, $\text{LPF}$ wattmeter has a full scale of $\text{300 W}$. The wattmeter can be used for loads supplied by $\text{300 V ac}$ mains with a ...

A single-phase transformer has maximum efficiency of $98 \%$. The core losses are $\text{80 W}$ and the equivalent winding resistance as seen from the primary side is $0....

A slip-ring induction motor is expected to be started by adding extra resistance in the rotor circuit. The benefit that is derived by adding extra resistance in the rotor...

The figure below shows an electrically conductive bar of square cross-section resting on a plane surface. The bar of mass of $\text{1 kg}$ has a depth of $\text{0.5 m}$ a...

A toroid made of $\text{CRGO}$ has an inner diameter of $\text{10 cm}$ and an outer diameter of $\text{14 cm}$. The thickness of the toroid is $\text{2 cm}$. $200$ turns ...

A household fan consumes $\text{60 W}$ and draws a current of $\text{0.3125 A (rms)}$ when connected to a $\text{230 V (rms) ac }$, $\text{50 Hz}$ single phase mains. The...

The power in a $\text{400 V}$ ($\text{rms}$, line-line) three-phase, three-wire $\text{RYB}$ sequence system is measured using the two wattmetters, as shown. The $\text{R...

A bar primary current transformer of rating $\text{1000/1 A}$, $\text{5VA}$, $\text{UPF}$ has $995$ secondary turns. It exhibits zero ratio error and phase of $30$ minute...

In the bridge circuit shown, the voltmeter $\text{V}$ showed zero when the value of the resistors are: $R_{1}=100\:\Omega$, $R_{2}=110\:\Omega$, and $R_{3}=90\:\Omega$. I...

Two $100\: \Omega$ resistors having tolerance $3\%$ and $4\%$ are connected in series. The effective tolerance of the series combination $\text{(in % rounded off to one d...

$I_1,\; I_2\: and \:I_3$ in the figure below are mesh currents. The correct set of mesh equations for these currents, in matrix form, is ____________$\begin{bmatrix} 3&-1...

The rms value of the phasor current $\underline{I}$ in the circuit shown $\text{(in amperes)}$ is _____.

In the circuit shown, the rms value of the voltage across the $ 100 \Omega$ resistor $\text{(in volts)}$ is _________.

The real power drawn by a balanced load connected to a $\text{400 V, 50 Hz,}$ balanced, symmetrical 3-phase, 3-wire, $RYB$ sequence mains is measured using the two-wattme...

A metallic strain gauge of resistance $R_X$ with a gauge factor of 2 is bonded to a structure made of a metal with modulus of elasticity of $200\: GN/m^2$. The value of $...

A $\text{1000/1 A, 5 VA, UPF}$ bar-primary measuring current transformer has $1000$ secondary turns. The current transformer exhibits a ratio error of $-0.1\%$ and a phas...

In the Maxwell-Wien bridge shown, the detector D reads zero when $C_1=100 nF$ and $R_1=100 k\Omega$. The Q factor of the coil is ______

In the circuit shown below, the safe maximum value for the current $I$ is _______$\text{1.0 A}$$\text{0.5 A}$$\text{0.1 A}$$\text{0.05 A}$

Three $400\;\Omega$ resistors are connected in delta and powered by a $400\;V\;(rms), \;50\;Hz,$ balanced symmetrical $R-Y-B$ sequence, three-phase three-wire mains. The ...

A series $R-L-C$ circuit is excited with an a.c. voltage source. The quality factor $(Q)$ of the circuit is given as $Q=30$. The amplitude of current in $\text{ampere}$ a...

In the circuit diagram, shown in the figure, $S_1$ was closed and $S_2$ was open for a very long time. At $t=0,\;S_1$ is opened and $S_2$ is closed. The voltage across th...

When the voltage across a battery is measured using a $d.c$. potentiometer, the reading shows $1.08\;V$. But when the same voltage is measured using a Permanent Magnet Mo...

The power delivered to a single phase inductive load is measured with a dynamometer type wattmeter using a potential transformer $(PT)$ of turns ratio $200:1$ and the cur...

In the a.c. bridge, shown in the figure, $R=10^3$ $\Omega$ and $C=10^{-7}$ $F$. If the bridge is balanced at a frequency $\omega_\circ$, the value of $\omega_\circ$ in ...

The magnetic flux density of an electromagnetic flowmeter is $100\;mWb/m^2$. The electrodes are wall-mounted inside the pipe having a diameter of $0.25\;m$. A voltage of ...

A current waveform, $i(t)$, shown in the figure, is passed through a Permanent Magnet Moving Coil $(PMMC)$ type ammeter. The reading of the ammeter up to two decimal plac...

Identify the instrument that does not exist:Dynamometer-type ammeter Dynamometer-type wattmeterMoving-iron voltmeterMoving-iron wattmeter