Electronics and Communication Gate 2017 Set-2 Questions with Answer

Ques 27 GATE 2017 SET-2

In the circuit shown, transistors Q₁ and Q₂ are biased at a collector current of 2.6 mA. Assuming that transistor current gains are sufficiently large to assume collector current equal to emitter current and thermal voltage of 26 mV, the magnitude of voltage gain V_o/V_S in the mid-band frequency range is (up to second decimal place).

Ques 28 GATE 2017 SET-2

In the voltage reference circuit shown in the figure, the op-amp is ideal and the transistors Q₁, Q₂,...,Q₃₂ are identical in all respects and have infinitely large values of common-emitter current gain (β). The collector current (I_C) of the transistors is related to their base-emitter voltage (V_BE) by the relation I_C=I_Sexp(V_BE/V_T). Where I_S is the saturation current. Assume that the voltage V_p shown in the figure is 0.7 V and the thermal voltage V_T=26 mV.

Ques 29 GATE 2017 SET-2

An n-channel enhancement mode MOSFET is biased at V_GS>V_TH and V_DS>(V_GS-V_TH). where V_GS is the gate-to-source voltage, V_DS is the drain-to-source voltage and V_TH is the threshold voltage. Considering channel length modulation effect to be significant, the MOSFET behaves as a

Ques 30 GATE 2017 SET-2

An npn bipolar junction transistor (BJT) is operating in the active region. If the reverse bias across the base-collector junction is increased, then

Ques 31 GATE 2017 SET-2

Consider an n-channel MOSFET having width W. length L. electron mobility in the channel μ_n and oxide capacitance per unit area C_ox. If gate-to-source voltage V_GS=0.7 V, drain-to-source voltage V_DS=0.1 V, (μ_nC_ox)=100 μA/V², threshold voltage V_TH=0.3 V and (W/L)=50, then the transconductance g_m (in mA/V) is

Ques 32 GATE 2017 SET-2

A MOS capacitor is fabricated on p-type Si (Silicon) where the metal work function is 4.1 eV and electron affinity of Si is 4.0 eV. E_C-E_F=0.9 eV, where E_C and E_F are the conduction band minimum and the Fermi energy levels of Si, respectively. Oxide ε_r=3.9. ε_o=8.85×10^-14F/cm, oxide thickness t_ox=0.1 μm and electronic charge q=1.6×10^-19 C. If the measured flat band voltage of this capacitor is -1 V. then the magnitude of the fixed charge at the oxide-semiconductor interface, in nC/cm² is

Ques 33 GATE 2017 SET-2

For a particular intensity of incident light on a silicon pn junction solar cell, the photocurrent density (J_L) is 2.5 mA/cm² and the open-circuit voltage (V_oc) is 0.451 V. Consider thermal voltage (V_T) to be 25 mV. If the intensity of the incident light is increased by 20 times, assuming that the temperature remains unchanged, V_oc (in volts) will be

Ques 34 GATE 2017 SET-2

Two n-channel MOSFETs. T1 and T2, are identical in all respects except that the width of T2 is double that of T1. Both the transistors are biased in the saturation region of operation, but the gate overdrive voltage (V_GS-V_TH) of T2 is double that of T1. where V_GS and V_TH are the gate-to-source voltage and threshold voltage of the transistors, respectively. If the drain current and transconductance of T1 are I_D1 and g_m1 respectively, the corresponding values of these two parameters for T2 are

Ques 35 GATE 2017 SET-2

An abrupt pn junction (located at x=0) is uniformly doped on both p and n sides. The width of the depletion region is W and the electric field variation in the x-direction is E(x). Which of the following figures represents the electric field profile near the pn junction?

Ques 36 GATE 2017 SET-2

The rank of the matrix

Ques 37 GATE 2017 SET-2

The general solution of the differential equation d²y/dx²+2dy/dx-5y=0 in terms of arbitrary constants K₁ and K₂ is

Ques 38 GATE 2017 SET-2

The smaller angle (in degrees) between the planes x+y+z=1 and 2x-y+2z=0 is

Ques 39 GATE 2017 SET-2

The residues of a function f(z)=1/((z-4)(z+1)³) are