Test: Electronic Devices & Circuits - 5 - Electrical Engineering (EE) MCQ

In a common emitter BJT amplifier, the maximum usable supply voltage is limited by

Assertion (A): In active region of CE output characteristics of BJT, collector current is nearly constant.

Reason (R): Base current in CE connection is very small.

The temperature of cathode is increased from 2500K to 2600K. The increase in thermionic emission current is about

Consider the following statement: At finite temperature, magnetic dipoles in a material are randomly oriented giving low magnetization. When magnetic field H is applied, the magnetization?

1. Increases with H
2. Decreases with H
3. Decreases with temp for constant H

Ferrites have

E_g is the band gap, A is pre-factor, k is Boltzmann constant? Which one of the following is the remaining grade of paper used in paper capacitor, besides the other two grade of paper-low and extra low loss?

Barkhausen criterion of oscillation is

The current through a PN Junction diode with v volts applied to the P region to the N region, where (I₀ is the reverse saturation current to the diode, m the ideality factor, k the Boltzmann constant, T the absolute temperature and q the magnitude of charge on an electron) is

The ratio of diffusion constant for hole D_P to the mobility for holes is proportional to

The carrier mobility in a semiconductor is 0.4 m²/Vs. Its diffusion constant at 300k will be (in m²/s).

During induction heating of metals which of the following is abnormally high?

Assertion (A): Alkali metals are used as emitters in phototubes.

Reason (R): Alkali metals have low work functions.

The output v-i characteristics of enhancement type MOSFET has

In a full wave rectifier, the current in each of the diodes flows for

In an ideal junction transistor the impurity concentration in emitter (E ), base (B) and collector (C) is such that

The rating of a transformer to deliver 100 watts of D.C. power to a load under half wave rectifier will be nearly

When a p-n junction is forward biased, the current remains zero till the applied voltage overcomes the barrier potential.

Which rectifier has the best ratio of rectification?

Assertion (A): A p-n junction is used as rectifier.

Reason (R): A p-n junction has low resistance in forward direction and high resistance in reverse direction.

In an integrated circuit the SiO₂ layers provide

For a n-channel JFET with r₀ = 10 kW, (V_Gs= 0 V, V_P = - 6 V)the drain resistance r_d at V_GS= - 3 V is given by

Which of the following are voltage controlled devices?