GATE ECE
Electronic Devices and VLSI
BJT and FET
Previous Years Questions

## Marks 1

An ideal MOS capacitor (p-type semiconductor) is shown in the figure. The MOS capacitor is under strong inversion with VG = 2V. The corresponding inve...
An npn bipolar junction transistor (BJT) is operating in the active region. If the reverse bias across the base-collector junction is increased, then
Consider the circuit shown in the figure. Assume base-to-emitter voltage VBE=0.8 V and common base current gain $$\left(\alpha\right)$$ of the transis...
For a narrow base PNP BJT, the excess minority carrier concentration ($$\bigtriangleup n_E$$ for emitter, $$\bigtriangleup p_B$$ for base, $$\bigtrian... The figure shows the I-V characteristics of a solar cell illuminated uniformly with solar light of power 100 mW/cm2. The solar cell has an area of 3 c... The Ebers-Moll model of a BJT is valid In the circuit shown in the figure, the BJT has a current gain (β) of 50. For an emitter-base voltage VEB = 600 mV, the emitter-collector voltage VEC(... If the base width in a bipolar junction transistor is doubled, which one of the following statements will be TRUE? An increase in the base recombination of a BJT will increase For a BJT the common base current gain$$\alpha$$= 0.98 and the collector base junction reverse bias saturation current ICO = 0.6μA. This BJT is conn... If the transistor in Figure is in saturation, then ... MOSFET can be used as a The breakdown voltage of a transistor with its base open is BVCEO with emitter open is BVCBO, then A BJT is said to be operating in the saturation region if The Ebers-Moll model is applicable to The Early-Effect in a bipolar junction transistor is caused by Channel current is reduced on application of a more positive voltage to the gate of a depletion mode n-channel MOSFET. The transit time of the current carriers through the channel of an FET decides its ____________characteristics. ## Marks 2 The injected excess electron concentration profile in the base region of an npn BJT, biased in the active region, is linear, as shown in the figure. I... An npn BJT having reverse saturation current$$I_s\;=\;10^{-15}\;A$$is biased in the forward active region with VBE = 700 mV. The thermal voltage (VT... Consider two BJT's biased at the same collector current with area A1 = 0.2 μm × 0.2 μm and A2 = 300 μm × 300 μm. Assuming that all other device parame... The channel resistance of an N-channel JFET shown in the figure below is 600 W when the full channel thickness (tch) of 10 μm is available for conduct... The channel resistance of an N-channel JFET shown in the figure below is 600 W when the full channel thickness (tch) of 10 μm is available for conduct... In a uniformly doped BJT, assume that NE, NB and NC are the emitter, base and collector dopings in atoms/cm3, respectively. If the emitter injection e... The DC current gain ($$\beta) of a BJT is 50. Assuming that the emitter injection efficiency is 0.995, the base transport factor is:
An n-channel JEFT has IDSS = 2 mA and Vp = −4 V. It's transconductance gm (in mA/V) for an applied gate-to-source voltage VGS of –2V is:...
An n-channel JFET has a pinch-off voltage VP = -5 V, VDS(max) = 20 V and gm = 2 mA/V. The minimum ‘ON’ resistance is achieved in the JEFT for...
In a transistor having finite B, the forward bias across the base emitter junction is kept constant and the reverse bias across the collector base jun...
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