ISRO Scientist or Engineer Electronics 2020

The following table gives the forward characteristics of a Si diode. Estimate the temperature of a diode junction.
(Given : $$\ln (0.2) = -1.609$$)

An n-channel MOS transistor is made on a p-type substrate with Na = $$10^{15} cm^{-3}$$ Find approximate depletion charge per unit area $$(Q_{d})$$ at strong inversion.
$$\left\{\ln(10)=2.3,\sqrt{0.046} \approx 0.215, n_{i}=10^{10} cm^{-3}\right\}$$

For a p-channel Si JFET, $$N_{a} = 3 \times 10^{16} cm^{-3}, N_{d}=10^{18} cm^{-3}$$. Channel thickness dimension is $$a = 0.33  \mu m$$. Find the approximate pinch-off voltage $$V_{p}. \left\{ n_{i}=10^{10} cm^{-3}, V_{r} = 26  mV, \ln (3) = 1.098 \right\}$$

Consider the circuit shown below

The power factor of the above circuit as seen by the source is

All the Three inductors are perfectly coupled as shown below,the value of total in (in Henry) across the terminal AB is

For a uniformly doped npn transistor, find the approximate emitter injection efficiency.
Given that:
$$N_{E}=2 \times 10^{18} cm^{-3}$$, $$N_{B}=10^{17} cm^{-3}, $$N_{C}=4 \times 10^{19} cm^{-3}, $$D_{E}=8 \frac{cm^{2}}{s}$$,$$D_{c}=28 \frac{cm^{2}}{s}$$, $$D_{B}=20 \frac{cm^{2}}{s}$$,$$ x_{E}=0.5 \mu m$$, $$x_{B}=0.3 \mu m$$

In a long p-type Si-bar with cross-sectional area = 0.5 $$cm^{2}$$ and $$ N_{a}.= 2 \times 10^{17} cm^{-3}$$ extra holes $$10^{16} cm^{-3}$$ are injected Assume $$\mu_{p}=500 \frac{cm^{2}}{Vs}$$, $$n_{i}=10^{10} cm^{-3}$$ and $$ \tau_{p}= 10^{-10}s $$find minority carrier lifetime.

In a p-type Si at 300 K and $$N_a = 8 \times 10^{15}  cm^{-3}$$, variation of space-charge density in the semiconductor as a function of surface potential is plotted, then select the true statement for weak inversion region. Given that $$p_{s}$$ and $$n_{s}$$ are hole and electron concentrations at the surface.

In order to ensure that the output voltage of an opamp zero, is when both its inputs are grounded

Consider the resistive network shown below, the value of Norton current across the terminal AB