Duduli

Extrinsic semiconductor is formed when some impurities added to pure form of semiconductor. The process of increase in conductivity by adding some impurity in small amount is called doping. Extrinsic semiconductor will be obtain by adding trivalent or pentavalent element to Germanium crystal. Therefore extrinsic semiconductor can be classified into two categories                  1. N-type semiconductor                  2. P-type semiconductor 

The pure form of the semiconductor is called intrinsic semiconductor. At absolute zero these are insulators. Conductivity depends upon temperature & increases with temperature.

Dc value of Ac is that value of steady current which sends same amount of charge through a circuit in same time as is done by Ac in one of cycle.

It is the forward voltage at which the current through the junction starts to increase rapidly.

It is the minimum reverse voltage at which pn junction breaks down with sudden rise in reverse current.

When external d.c voltage applied to the junction is in such a direction that it cancels the potential barrier, thus permitting current flow, it is called forward biasing.

A junction diode which acts as a variable capacitor under changing reverse bias is known as a varactor diode.

A transistor consists of two pn- junction formed by sandwiching either p- type or n- type Semiconductor between a pair of opposite types. Accordingly there are two types of transistors namely  (i) n-p-n transistor (ii) p-n-p transistor

A tunnel diode is a pn junction that exhibits negative resistance between two values of forward voltage(i.e between peak point voltage and valley point voltage). A conventional diode exhibits positive resistance when it is forward biased or reverse biased. However, if a Semiconductor junction diode is heavily doped with impurities, it exhibits negative resistance (i.e current decreases as the voltage is increased) in certain regions in the forward direction. Such a diode is called tunnel diode.

A photo diode is a reversed-biased silicon or germanium pn junction in which reverse current increases when the junction is exposed to light. The reverse current in a photo-diode is directly proportional to the intensity of light falling on it's on junction.This means that greater the intensity of light falling on the pn junction of diode the greater will be the reverse current.

Answer:- It is defined as the ratio of r.m.s. value of a.c. component to that of d.c. value of d.c. component in the output of the rectifier.

Answer:- Efficiency of a rectifier is defined as the ratio between d.c. power output to a.c. input power.

Answer:- If the plate of the vacuum tube is not given a positive potential, electrons emitted by the filament get collected around it to form a cloud of negative charge.This is called space charge.If not removed it will stop thermonic emission.

Answer:- A rectifier is a semiconductor device which convert alternating current into direct current. ★It is of two types,                  (i) Half wave rectifier                  (ii) Full wave rectifier

Answer:- When the intrinsic semiconductor is doped by trivalent impurity then p-type semiconductor is form. ★It is called p-type semiconductor because the majority charge carrier is holes(means positive charge).

Answer:- When an intrinsic semiconductor is doped by a pentavalent impurity n-type semiconductor is form. ★ It is called n-type semiconductor because the majority charge carrier is free  electron.

Answer:- It is a special type of semiconductor diode named after its inveter c.zener. It is designed to operate under reverse bias in breakdown voltage,and used as voltage regulator. The symbol of zener diode is

Answer:- NOT gate is also called as inverter because it's output signal is just inverse of it's input   signal. I.e if input signal value is ‘1’ then it's output signal value is ‘0’ or if input signal value is ‘0’ then it's output signal value is ‘1’.

Answer:- A p-n junction is formed when we add a pentavalent impurity in a p-type semiconductor. l.e in a p-n junction one side is p-type semiconductor & another side is n-type semiconductor with forming a depletion region  in their junction. A p-n junction is symbolically represented as, A p-n junction is generally called a Semiconductor diode.