GATE EC BJT and MOSFET Amplifiers questions

The oscillator circuit shown in the figure,

The transistor shunt regulator shown in the figure is has a regulated output voltage of $10 \mathrm{~V}$, when the input varies from $20 \mathrm{~V}$ to $30 \mathrm{~V}$. The relevant parameters for the zener diode and the transistor are: $\mathrm{V}_{\text{Z}}=9.5, \mathrm{~V}_{\text{SE }}=0.3 \mathrm{~V}, \beta=99$. Neglect the current through …

An npn $\text{BJT}$ has $\mathrm{gm}=38 \mathrm{~m} \mathrm{~A} / \mathrm{V}, \mathrm{C}_{u}=10^{-14} \mathrm{~F}$, $C_{\pi}=4 \times 10^{-13} \mathrm{~F}$, and $D C$ current gain $\beta_{0}=90$. For this transistor $f_{\mathrm{T}}$ and $f_{\beta}$ are

The current gain of a bipolar transistor drops at high frequencies because of

Introducing a resistor in the emitter of a common amplifier stabilizes the $\text{dc}$ operating point against variations in

In the differential amplifer of the figure, if the source resistance of the current source $I_{E E}$ is infinite, then the common-mode gain is

In the circuit of the figure, assume that the transistor is in active region. It has a large $\beta$ and its base-emitter voltage is $0.7 \mathrm{~V}$. The value of $\mathrm{I}_{\mathrm{c}}$ is

A Darlington emitter - follower circuit is sometimes used in the output stage of a $\text{TTL}$ gate in order to

Crossover distortion behaviour is characteristic of

In the cascade amplifier shown in the given figure, if the common - emitter stage $\left(Q_{1}\right)$ has a transconductance $\mathrm{gm}_{1}$, and the common base stage $\left(Q_{2}\right)$ has a transconductance $\mathrm{gm}_{2^{\prime}}$, then the overall transconductance $g\left(=i_{0} / v_{1}\right)$ of the cascade amplifier is

The early effect in a bipolar junction transistor is caused by

An amplifier is assumed to have a single-pole high-frequency transfer function. The rise time of its output response to a step function input is $35\;\text{nsec}$. The upper $-3 \; d B$ frequency (in $\text{MHz}$) for the amplifier to a sinusoidal input is approximately at

An $\text{npn}$ transistor (with $\mathrm{C}=0.3 \; \mathrm{pF}$ ) has a unity gain cutoff frequency $f_{\mathrm{T}}$ of $400 \; \mathrm{MHz}$ at a $\text{dc}$ bias current $I_{c}=1 \mathrm{~mA}$. The value of its $C_{\mu}$ (in $\mathrm{~pF}$ ) is approximately $\left(\mathrm{V}_{\mathrm{T}}=26 \; \mathrm{mV}\right)$

An $n$-channel $\text{JEFT}$ has $\mathrm{I}_{\mathrm{DSS}}=2 \mathrm{~mA}$ and $\mathrm{V}_{p}=-4 \mathrm{~V}$. Its transconductance $\mathrm{gm}$ (in milliohm) for an applied gate-to-source voltage $\mathrm{V}_{\mathrm{GS}}$ of $-2 \mathrm{~V}$ is

In the $\text{MOSFET}$ amplifier of the figure is the signal outputs $V_{1}$ and $V_{2}$ obey the relationship

In a series regulated power supply circuit, the voitage gain $A_{v}$ of the 'pass' transistor satisfies the condition

A multistage amplifier has a low-pass response with three real poles at $s=-\omega_{1}-\omega_{2}$ and $\omega_{3}$. The approximate overall bandwidth $\mathrm{B}$ of the amplifier will be given by

The emitter coupled pair of $\text{BJT's}$ gives a linear transfer relation between the differential output voltage and the differenital input voltage $\mathrm{V}_{i d }$ only when the magnitude of $V_{i d}$ is less $\alpha$ times the thermal voltage, where $\alpha$ is

In a differential amplifier, $\text{CMRR}$ can be improved by using an increased

Two identical $\text{FETs}$, each characterised by the parameters $g_m$ and $r_d$ are connected in parallel. The composite $\text{FET}$ is then characterised by the parameters