Recent questions tagged impedance

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GATE ECE 2020 | Question: 13
The impedances $Z=jX,$ for all $X$ in the range $\left ( -\infty ,\infty \right )$, map to the Smith chart as a circle of radius $1$ with centre at $(0, 0)$. a point at the centre of the chart. a line passing through the centre of the chart. a circle of radius $0.5$ with centre at $(0.5, 0)$.

The impedances $Z=jX,$ for all $X$ in the range $\left ( -\infty ,\infty \right )$, map to the Smith chart asa circle of radius $1$ with centre at $(0, 0)$.a point at the...

1.9k points

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go_editor asked Feb 13, 2020

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GATE ECE 2020 | Question: 21
A transmission line of length $3\lambda /4$ and having a characteristic impedance of $50$ $\Omega$ is terminated with a load of $400 \Omega$. The impedance (rounded off to two decimal places) seen at the input end of the transmission line is __________ $\Omega$.

A transmission line of length $3\lambda /4$ and having a characteristic impedance of $50$ $\Omega$ is terminated with a load of $400 \Omega$. The impedance (rounded off t...

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go_editor asked Feb 13, 2020

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GATE ECE 2020 | Question: 46
For a $2$-port network consisting of an ideal lossless transformer, the parameter $S_{21}$ (rounded off to two decimal places) for a reference impedance of $10 \Omega$, is __________.

For a $2$-port network consisting of an ideal lossless transformer, the parameter $S_{21}$ (rounded off to two decimal places) for a reference impedance of $10 \Omega$, i...

1.9k points

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go_editor asked Feb 13, 2020

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GATE ECE 2016 Set 1 | Question: 25
The propagation constant of a lossy transmission line is $(2+j5) m^{-1}$ and its characteristic impedance is $(50+j0) \Omega$ at $\omega = 10^6 rad \: s^{-1}$ ... $L = 250 \: \mu H/m, C = 0.2 \: \mu F/m, R=50 \: \Omega /m, \: G=0.04 \: S/m$

The propagation constant of a lossy transmission line is $(2+j5) m^{-1}$ and its characteristic impedance is $(50+j0) \Omega$ at $\omega = 10^6 rad \: s^{-1}$. The values...

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Milicevic3306 asked Mar 27, 2018

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GATE ECE 2016 Set 1 | Question: 31
A network consisting of a finite number of linear resistor (R), inductor (L), and capacitor (C) elements, connected all in series or all in parallel, is excited with a source of the form ... $\sum_{k=1}^{3} a_k\cos(k\omega_0t+\phi_k) \\$ $\sum_{k=1}^{2} a_k\cos(k\omega_0t+\phi_k)$

A network consisting of a finite number of linear resistor (R), inductor (L), and capacitor (C) elements, connected all in series or all in parallel, is excited with a so...

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Milicevic3306 asked Mar 27, 2018

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GATE ECE 2015 Set 3 | Question: 53
Consider the $3\:m$ long lossless air-filled transmission line shown in the figure. It has a characteristic impedance of $120\pi\: \Omega,$ is terminated by a short circuit, and is excited with a frequency of $37.5\: MHz.$ What is the nature of the input impedance $(Z_{in})?$ Open Short Inductive Capacitive

Consider the $3\:m$ long lossless air-filled transmission line shown in the figure. It has a characteristic impedance of $120\pi\: \Omega,$ is terminated by a short circu...

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Milicevic3306 asked Mar 27, 2018

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GATE ECE 2014 Set 4 | Question: 11
If the emitter resistance in a common-emitter voltage amplifier is not bypassed, it will reduce both the voltage gain and the input impedance reduce the voltage gain and increase the input impedance increase the voltage gain and reduce the input impedance reduce both the voltage gain and the input impedance

If the emitter resistance in a common-emitter voltage amplifier is not bypassed, it willreduce both the voltage gain and the input impedancereduce the voltage gain and in...

16.0k points

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Milicevic3306 asked Mar 26, 2018

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GATE ECE 2014 Set 4 | Question: 24
For an antenna radiating in free space, the electric field at a distance of $1$ km is found to be $12 \: mV/m$. Given that intrinsic impedance of the free space is $120 \pi \: \Omega$, the magnitude of average power density due to this antenna at a distance of $2$ km from the antenna (in $nW/m^2$) is _________.

For an antenna radiating in free space, the electric field at a distance of $1$ km is found to be $12 \: mV/m$. Given that intrinsic impedance of the free space is $120 \...

16.0k points

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Milicevic3306 asked Mar 26, 2018

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GATE ECE 2014 Set 4 | Question: 33
For the two-port network shown in the figure, the impedance (Z) matrix (in $\Omega$) is $\begin{bmatrix} 6 & 24 \\ 42 & 9 \end{bmatrix}$ $\begin{bmatrix} 9 & 8 \\ 8 & 24 \end{bmatrix}$ $\begin{bmatrix} 9 & 6 \\ 6 & 24 \end{bmatrix}$ $\begin{bmatrix} 42 & 6 \\ 6 & 60 \end{bmatrix}$

For the two-port network shown in the figure, the impedance (Z) matrix (in $\Omega$) is$\begin{bmatrix} 6 & 24 \\ 42 & 9 \end{bmatrix}$$\begin{bmatrix} 9 & 8 \\ 8 & 24 \e...

16.0k points

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Milicevic3306 asked Mar 26, 2018

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GATE ECE 2014 Set 3 | Question: 25
In the following figure, the transmitter $Tx$ sends a wideband modulated $RF$ signal via a coaxial cable to the receiver $Rx$. The output impedance $Z_{T}$ of $Tx$, the characteristic impedance $Z_{0}$ of the cable and the input impedance ... $Z_{R}\neq Z_{0}$ Impedance mismatches do NOT result in signal distortion but reduce power transfer efficiency

In the following figure, the transmitter $Tx$ sends a wideband modulated $RF$ signal via a coaxial cable to the receiver $Rx$. The output impedance $Z_{T}$ of $Tx$, the ...

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Milicevic3306 asked Mar 26, 2018

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GATE ECE 2014 Set 3 | Question: 32
In the circuit shown in the figure, the angular frequency $\omega$ (in rad/s), at which the Norton equivalent impedance as seen from terminals $b-b'$ is purely resistive, is ________.

In the circuit shown in the figure, the angular frequency $\omega$ (in rad/s), at which the Norton equivalent impedance as seen from terminals $b-b'$ is purely resistive,...

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Milicevic3306 asked Mar 26, 2018

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GATE ECE 2014 Set 2 | Question: 24
To maximum power transfer, a lossless transmission line is to be matched to a resistive load impedance via a $\lambda/4$ transformer as shown. The characteristic impedance (in $\Omega$) of the $\lambda$/4 transformer is ___________.

To maximum power transfer, a lossless transmission line is to be matched to a resistive load impedance via a $\lambda/4$ transformer as shown. The c...

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Milicevic3306 asked Mar 26, 2018

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GATE ECE 2014 Set 2 | Question: 54
In the transmission line shown, the impedance $Z_{\text{in}}$ (in ohms) between node A and the ground is _________.

In the transmission line shown, the impedance $Z_{\text{in}}$ (in ohms) between node A and the ground is _________.

16.0k points

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Milicevic3306 asked Mar 26, 2018

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GATE ECE 2014 Set 1 | Question: 11
A good current buffer has low input impedance and low output impedance low input impedance and high output impedance high input impedance and low output impedance high input impedance and high output impedance

A good current buffer haslow input impedance and low output impedancelow input impedance and high output impedancehigh input impedance and low output impedancehigh input ...

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Milicevic3306 asked Mar 25, 2018

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GATE ECE 2014 Set 1 | Question: 54
For a parallel plate transmission line, let $v$ be the speed of propagation and $Z$ be the characteristic impedance. Neglecting fringe effects, a reduction of the spacing between the plates by a factor of two results in halving of $v$ and no change in $Z$ no changes in $v$ and halving of $Z$ no change in both $v$ and $Z$ halving of both $v$ and $Z$

For a parallel plate transmission line, let $v$ be the speed of propagation and $Z$ be the characteristic impedance. Neglecting fringe effects, a reduction of the spacin...

16.0k points

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Milicevic3306 asked Mar 25, 2018

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GATE ECE 2014 Set 1 | Question: 55
The input impedance of a $\dfrac{\lambda}{8}$ section of a lossless transmission line of characteristic impedance $50\: \Omega$ is found to be real when the other end is terminated by a load $Z_{L} (=R + jX)\Omega.$ If $X$ is $30\:\Omega ,$ the value of $R ( \text{in} \:\Omega )$ is _______.

The input impedance of a $\dfrac{\lambda}{8}$ section of a lossless transmission line of characteristic impedance $50\: \Omega$ is found to be real when the other end is...

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Milicevic3306 asked Mar 25, 2018

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GATE ECE 2013 | Question: 23
A source $v_{s}(t) = V\cos100\:\pi t$ has an internal impedance of $(4 + j3)\:\Omega.$ If a purely resistive load connected to this source has to extract the maximum power out of the source, its value in $\Omega$ should be $3$ $4$ $5$ $7$

A source $v_{s}(t) = V\cos100\:\pi t$ has an internal impedance of $(4 + j3)\:\Omega.$ If a purely resistive load connected to this source has to extract the maximum powe...

16.0k points

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Milicevic3306 asked Mar 25, 2018

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GATE ECE 2013 | Question: 15
In a voltage-voltage feedback as shown below, which one of the following statements is TRUE if the gain $k$ is increased? The input impedance increases and output impedance decreases The input impedance increases and output ... also increases The input impedance decreases and output impedance also decreases The input impedance decreases and output impedance increases

In a voltage-voltage feedback as shown below, which one of the following statements is TRUE if the gain $k$ is increased? The input impedance increases and output impedan...

16.0k points

107 views

Milicevic3306 asked Mar 25, 2018

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GATE ECE 2012 | Question: 21
The impedance looking into nodes $1$ and $2$ in the given circuit is $50\:\Omega$ $100\:\Omega$ $5\:k\Omega$ $10.1\:k\Omega$

The impedance looking into nodes $1$ and $2$ in the given circuit is$50\:\Omega$$100\:\Omega$$5\:k\Omega$$10.1\:k\Omega$

16.0k points

87 views

Milicevic3306 asked Mar 25, 2018

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GATE ECE 2012 | Question: 16
A coaxial cable with an inner diameter of $1\:mm$ and outer diameter of $2.4\:mm$ is filled with a dielectric of relative permittivity $10.89$. Given $\mu_0=4\pi\times10^{-7}\:H/m$, $\varepsilon_0=\frac{10^{-9}}{36\pi}\:F/m$, the characteristic impedance of the cable is $330\:\Omega$ $100\:\Omega$ $143.3\:\Omega$ $43.4\:\Omega$

A coaxial cable with an inner diameter of $1\:mm$ and outer diameter of $2.4\:mm$ is filled with a dielectric of relative permittivity $10.89$. Given $\mu_0=4\pi\times10^...

16.0k points

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Milicevic3306 asked Mar 25, 2018

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GATE ECE 2012 | Question: 10
The average power delivered to an impedance $(4-j3)\:\Omega$ by a current $5\cos(100\pi t+100)\:A$ is $44.2\:W$ $50\:W$ $62.5\:W$ $125\:W$

The average power delivered to an impedance $(4-j3)\:\Omega$ by a current $5\cos(100\pi t+100)\:A$ is$44.2\:W$$50\:W$$62.5\:W$$125\:W$

16.0k points

68 views

Milicevic3306 asked Mar 25, 2018

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GATE ECE 2018 | Question: 21
A lossy transmission line has resistance per unit length $R=0.05\:\Omega/m.$ The line is distortionless and has characteristic impedance of $50\:\Omega.$ The attenuation constant (in $\text{Np/m}$, correct to three decimal places) of the line is ________.

A lossy transmission line has resistance per unit length $R=0.05\:\Omega/m.$ The line is distortionless and has characteristic impedance of $50\:\Omega.$ The attenuation ...

1.6k points

145 views

gatecse asked Feb 19, 2018

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GATE ECE 2018 | Question: 10
The points $\text{P, Q, and R}$ shown on the Smith chart (normalized impedance chart) in the following figure represent: $\text{P: Open Circuit, Q: Short Circuit, R: Matched Load}$ $\text{P: Open Circuit, Q: Matched Load, R: Short Circuit}$ $\text{P: Short Circuit, Q: Matched Load, R: Open Circuit}$ $\text{P: Short Circuit, Q: Open Circuit, R: Matched Load}$

The points $\text{P, Q, and R}$ shown on the Smith chart (normalized impedance chart) in the following figure represent: $\text{P: Open Circu...

1.6k points

148 views

gatecse asked Feb 19, 2018

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GATE ECE 2018 | Question: 3
A good transimpedance amplifier has low input impedance and high output impedance high input impedance and high output impedance high input impedance and low output impedance low input impedance and low output impedance

A good transimpedance amplifier haslow input impedance and high output impedancehigh input impedance and high output impedancehigh input impedance and low output impedanc...

1.6k points

131 views

gatecse asked Feb 19, 2018

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