GATE ECE
Electronic Devices and VLSI
PN Junction
Previous Years Questions

## Marks 1

A p-type semiconductor with zero electric field is under illumination (low level injection) in steady state condition. Excess minority carrier density...
A region of negative differential resistance is observed in the current voltage characteristics of a silicon PN junction if
In the circuit shown below, the Zener diode is ideal and the Zener voltage is 6V. The output voltage V0 (in volts) is ________. ...
When the optical power incident on a photodiode is 10μW and the responsivity is 0.8 A/W, the photocurrent generated (in μA) is ________.
In a forward biased P-N junction diode, the sequence of events that best describes the mechanism of current flow is
Which of the following is NOT associated with a P-N junction?
In the following limiter circuit, an input voltage $${\mathrm V}_\mathrm i\;=\;10\sin\left(100\mathrm{πt}\right)$$ applied. Assume that the diode drop...
In a p+n junction diode under reverse bias, the magnitude of electric field is maximum at
In the figure, a silicon diode is carrying a constant current of 1 mA. When the temperature of the diode is 20°C, VD is found to be 700 mV. If the tem...
The static characteristic of an adequately forward biased p-n junction is a straight line, if the plot is of
For small signal a.c. operation, a practical forward biased diode can be modeled as
The diffusion potential across a P-N junction
A zener diode works on the principle of
The depletion capacitance, CJ, of an abrupt P-N junction with constant doping on either side varies with reverse bias, VR , as
In a junction diode

## Marks 2

For a particular intensity of incident light on a silicon pn junction solar cell, the photocurrent density (JL) is 2.5 mA/cm2 and the open-circuit vol...
Consider the charge profile shown in the figure. The resultant potential distribution is best described by ...
Consider a region of silicon devoid of electrons and holes, with an ionized donor density of $${\mathrm N}_\mathrm d^+=10^{17}\;\mathrm{cm}^{-3}$$. Th...
The electric field profile in the depletion region of a p-n junction in equilibrium is shown in the figure. Which one of the following statements is N...
The built-in potential of an abrupt p-n junction is 0.75V. If its junction capacitance (CJ) at a reverse bias (VR) of 1.25V is 5pF, the value of CJ (i...
Consider an abrupt PN junction (at T = 300 K) shown in the figure. The depletion region width Xn on the N-side of the junction is 0.2 µm and the permi...
In the circuit shown below, the knee current of the ideal Zener diode is 10 mA. To maintain 5V across RL, the minimum value of RL in Ω and the minimum...
In the circuit below, the diode is ideal. The voltage V is given by ...
A P+-N junction has a built-in potential of 0.8 V. The depletion layer width at a reverse bias of 1.2V is 2 µm. For a reverse bias of 7.2 V, the deple...
The Zener diode in the regulator circuit shown in figure has a Zener voltage of 5.8 Volts and a Zener knee current of 0.5 mA. The maximum load current...
A Silicon PN junction diode under reverse bias has depletion region of width 10 µm. The relative permittivity of Silicon, ɛr = 11.7 and the permittivi...
At 300 K, for a diode current of 1 mA, a certain germanium diode requires a forward bias of 0.1435 V. Where as a certain silicon diode requires a forw...
Choose proper substitutes for X and Y to make the following statement correct Tunnel diode and Avalanche photodiode are operated in X bias and Y bias ...
The built-in potential (Diffusion Potential) in a p-n junction
The 6 V Zener diode shown in figure has zero Zener resistance and a knee current of 5 mA. The minimum value of R, so that the voltage across it does n...
The small signal capacitances of an abrupt P+−N junction is 1 nF at zero bias. If the built-in voltage is 1 volt, the capacitance at a reverse bias vo...
Referring to the figure. The switch S is in position 1 initially and steady state conditions exist from time t = 0 to t = t0. At t = t0, the switch is...
The diffusion capacitance of a P-N junction
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