Exams › GATE › Technical

For an ideal MOSFET biased in saturation, the magnitude of the small signal current gain for a common drain amplifier is

1. 0
2. 1
3. 100
4. infinite

Correct answer: infinite

Solution

For an ideal MOSFET the gate (input) current is zero, so the small-signal input current of a common-drain (source-follower) stage is essentially zero while the output current is finite. The current gain (output/input) is therefore infinite.

Related GATE Technical questions

• The most commonly used relay, for the protection of an alternator against loss of excitation, is
• The geometric mean radius of a conductor, having four equal strands with each strand of radius ‘r’, as shown in the figure below, is
• The Bode magnitude plot of a first order stable system is constant with frequency. The asymptotic value of the high frequency phase, for the system, is −180°. This system has
• In the circuit shown below, a three-phase star-connected unbalanced load is connected to a balanced three-phase supply of 100√3 V with phase sequence ABC. The star connected load has Z_A = 10 Ω and Z_B = 20∠60° Ω. The value of Z_C in Ω, for which the voltage difference across the nodes n and n' is zero, is
• A charger supplies 100 W at 20 V for charging the battery of a laptop. The power devices, used in the converter inside the charger, operate at a switching frequency of 200 kHz. Which power device is best suited for this purpose?
• A long conducting cylinder having a radius ‘b’ is placed along the z axis. The current density is J = Jₐ r³ ẑ for the region r < b where r is the distance in the radial direction. The magnetic field intensity (H) for the region inside the conductor (i.e. for r < b) is

⚔️ Practice GATE Technical free + battle 1v1 →