GATE EC question library

A Silicon sample $\mathrm{A}$ is doped with $10^{18}$ atoms $/ \mathrm{cm}^{3}$ of Boron. Another sample $\mathrm{B}$ of identical dimensions is doped with $10^{18}$ atoms $/ \mathrm{cm}^{3}$ of Phosphorus. The ratio of electron to hole mobility is $3.$ The ratio of conductivity of the sample $\mathrm{A}$ to $\mathrm{B}$ is

A Silicon PN junction diode under reverse bias has depletion region of width $10 \; \mu \mathrm{m}$. The relative permittivity of Silicon,$\varepsilon_{r}=11.7$ and the permittiveity of free space $\varepsilon_{0}=8.85 \times 10^{-12} \mathrm{~F/m}$. The depletion capacitance of the diode per square meter is

For an $\text{npn}$ transistor connected as shown in the figure, $V_{B E}=0.7$ volts. Given that reverse saturation current of the junction at room temperature $300^{\circ} \mathrm{K}$ is $10^{-13} \mathrm{~A}$, the emitter current is

The voltage $e_{0}$ indicated in the figure has been measured by an ideal voltmeter. Which of the following can be calculated?

The $\text{OP-amp}$ circuit shown in the figure is a filter. The type of filter and its cut-off frequency are respectively

In an ideal differential amplifier shown in the figure, a large value of $\left(R_{E}\right)$.

For an $n$-channel $\text{MOSFET}$ and its transfer curve shown in the figure, the threshold voltage is

The circuit using a $\text{BJT}$ with $\beta=50$ and $\mathrm{V}_{\mathrm{BE}}=0.7 \mathrm{~V}$ is shown in the figure. The base current $\mathrm{I}_{\mathrm{B}}$ and collector voltage $\mathrm{V}_{\mathrm{C}}$ are respectively

The zener diode in the regulator circuit shown in the figure has a Zener voltage of $5.8$ volts and a Zener knee current of $0.5 \mathrm{~mA}$. The maximum load current drawn from this circuit ensuring proper functioning over the input voltage range between $20$ and $30$ volts, is

The transistors used in a portion of the TTL gate shown in the figure have a $\beta=100$. The base-emitter voltage of is $0.7 \mathrm{~V}$ for a transistor in active region and $0.75 \mathrm{~V}$ for a transistor in saturation. If the sink current $I=1 \mathrm{~mA}$ and the output is at logic $0,$ then the current $I_{R}$ will be equal to

The Boolean expression for the truth table shown is …

Both transistors $\mathrm{T} 1$ and $\mathrm{T} 2$ show in the figure, have a threshold voltage of $1$ Volts. The device parameters $\mathrm{K}_1$ and $\mathrm{K}_2$ of $\mathrm{T} 1$ and $\mathrm{T} 2$ are, respectively, $36 \; \mu \mathrm{A/V}^{2}$ and $9 \; \mu \mathrm{A} / \mathrm{V}^{2}$. The output voltage $V_{0}$ is

The present output $Q_{n}$ of an edge triggered JK flip-flop is logic $0.$ If $\mathrm{J}=1$, then $\mathrm{Q}_{n+1}$

The given figure shows a ripple counter using positive edge triggered flip-flops. If the present state of the counter is $Q_{2} \; Q_{1} \; Q_{0}=011$, then its next state $\left(Q_{2} \; Q_{1} \; Q_{n}\right)$ will be

What memory address range is $\text{NOT}$ represented by chip $\# \; 1$ and chip $\# \; 2$ in the figure $\text{A}_{0}$ to $\text{A}_{15}$ in this figure are the address lines and $\text{CS}$ means Chip Select.

The output $y(t)$ of a linear time invariant system is related to its input $x(t)$ by the following equation: $y(t)=0.5 x\left(t-t_{d}+\mathrm{T}\right)+x\left(t-t_{d}\right)+0.5 x\left(t-t_{d}-\mathrm{T}\right)$. The filter transfer function $\mathrm{H}(\omega)$ of such a system is given by

Match the following and choose the correct combination. …

A signal $x(n)=\sin \left(\omega_{0} n+\phi\right)$ is the input to a linear time-invariant system having a frequency response $\text{H}(e^{j \omega})$. If the output of the system $A x\left(n-n_{0}\right)$, then the most general form of $\angle \mathrm{H}\left(\mathrm{e}^{j \omega}\right)$ will be

For a signal $x(f)$ the fourier transform is $X(f)$. Then the inverse Fourier transform of $X(3 f+2)$ is given by

The polar diagram of a conditionally stable system for open loop gain $\text{K}=1$ is shown in the figure. The open loop transfer function of the system is known to be stable. The closed loop system is stable for