ISRO Scientist or Engineer Electronics 2020

The Transfer characteristic of the different types of MOSFETs is shown below , where $$I_{D}$$ is drain current and $$V_{GS}$$ is the Gate source volatge , the correct combination of MOSFET w.r.t to transfer characteristics is

Accept impurity concentartion of si at 300 K is $$10^{19} cm^{-3}$$ Calculate the concentration of donor impurity atoms that should be added so that Si is n type and the Fermi Energy is 26 meV below the conduction band edge (Given: Effective density state $$N_{c} = 2.7 \times 10^{19} cm^{-3}$$ and Thermal Volatage $$(V_{T})$$ at 300 K is 26 mv)

The electric field between twoparallel plates placed in vacuum is ‘E’. If a slab of dielectric constant $$\sqrt{3}$$ is inserted in between the plates such that the normal to the boundary makes an angle $$45^\circ$$ with the lines of electric force in between the plates. Find the angle $$(\theta)$$ between the electric lines in the medium between the plates (vacuum) and dielectrié slab.

Two parallel perfectly conducting planes of infinite extent are placed ‘b’ distance apart so that the cut-off frequency of the lowest order TE mode is 15 GHz. If additionally, two perfectly conducting planes are placed 10 mm_apart so as to form a rectangular wave guide as shown in figure. Find out the cutoff frequency of $$TE_{11}$$ mode.

Consider the AND logic circuit in which $$V_{2} = 3  V$$ and $$V_{1}$$ lies between 0 to 5 volts The output Voltage is $$V_{o}$$ .The cut-in Voltage of the Diode $$D_{1}$$ and $$D_{2}$$ is 0.6 Volts. The output voltage $$V_{o}$$ versus $$V_{1}$$ corresponding to the below network is

Following are the applications of a Buck and Boost Converters respectively
A. Regulated DC powersupplies
B. Regenerative braking of DC motors~
C .DC motor speed control.

In a MOSFET $$SiO_{2}$$, breaks down at electric field of the order of $$5 \times 10^{6}  V/cm$$. For a gate oxide of thickness 1000 A and channel thickness of $$2 \mu m$$, what is the maximum $$V_{GS}$$ it can with stand ?

Which of the followingis false for a Thyristor?
A. Thyristor is a majority-carrier device
B. The forward-bias portion of Thyristors i-v characteristics has two stable operating regions.
C.The forward-bias portion of Thyristors i-v characteristics has one stable operating regions.
D. The negative gate current turns off the Thyristor.

The Zener regulator circuit shown below consists of si based Zener diode and Ge diode . The cut-in Voltage of Ge diode is 0.2 volts where cut in voltage of si-diode is 0.7 Volts.

The output Voltage $$( V_{o})$$ of the Zener Regulator Circuit is

The asymptotic bode plot for the gain magnitude of a minimum phase System G(s) is shown in figure below

The steady state error for ramp input is