Electronic Devices

In a common base amplifier, the phase difference between the input signal voltage and output voltage is

In a common base mode of a transistor, the collector current is $$5.488$$ $$mA$$ for an emitter current of $$5.60mA.$$ The value of the base current amplification factor $$\left( \beta \right)$$ will be

A working transistor with its three legs marked $$P,Q$$ and $$R$$ is tested using a multi-meter. No conduction is found between $$P$$ and $$Q$$. By connecting the common (negative) terminal of the multi-meter to $$R$$ and the other (positive) terminal to $$P$$ or $$Q,$$ some resistance is seen on the multi-meter. Which of the following is true for the transistor?

The ratio (R) of output resistance r₀, and the input resistance ri in measurements of input and output characteristics of a transistor is typically in the range:

An unknown transistor needs to be identified as a npn or pnp type. A multimeter, with + ve and − ve terminals, is used to measure resistance between different terminals of transistor. If terminal 2 is the base of the transistor then which of the following is correct for a pnp transistor ?

If the ratio of the concentration of electrons to that of holes in a semiconductor is $${7 \over 5}$$ and the ratio of currents is $${7 \over 4},$$ then what is the ratio of their drift velocities?

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At absolute zero, Si acts as

By increasing the temperature, the specific resistance of a conductor and a semiconductor

The energy band gap is maximum in

A strip of copper and another of germanium are cooled from room temperature to $$80K.$$ The resistance of

The difference in the variation of resistance with temperature in a metal and a semiconductor arises essentially due to the difference in the

In the middle of the depletion layer of a reverse- biased $$p$$-$$n$$ junction, the

A piece of copper and another of germanium are cooled from room temperature to $$77K,$$ the resistance of

The manifestation of band structure in solids is due to

When $$p$$-$$n$$ junction diode is forward biased then

The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength shorter than $$2480$$ $$nm$$ is incident on it. The band gap in $$(eV)$$ for the semiconductor is

In a full wave rectifier circuit operating from $$50$$ $$Hz$$ mains frequency, the fundamental frequency in the ripple would be

A solid which is not transparent to visible light and whose conductivity increases with temperature is formed by