Explain working of n-p-n transistor in unbiased condition.

Explain working of n-p-n transistor in unbiased condition.
by

1 Answer

Answer :

Construction of NPN transistor: For an unbiased transistor no external power supplies are connected to it. Base is sandwiched between collector & emitter terminal. It is thin & lightly doped layer. Emitter & collector layers are wider than base & heavily doped than base. A transistor is formed of two P-N junctions. For unbiased P-N junctions, the depletion regions are formed. The fig(a) shows the depletion regions formed at the B-E and C-B junctions of n-p-n transistor. Due to this depletion region any kind of current will not flow due to majority carrier but very small amount of current will flow because of thermally generated minority carrier. To break this depletion layer there is a need of providing external power supply to transistor & this process is known as Biasing.

image

by

Related questions

With neat diagram explain working of NPN transistor.

Description : With neat diagram explain working of NPN transistor.

Last Answer : N-p-n transistor is made by sandwiching thin layer of p-type semiconductor between two layers of n-type semiconductor. It has three terminals - Emitter, Base and collector. The npn transistor has two ... up in the collector as it is more positive. In this way, current flows in the transistor.

Compare P.N.P and N.P.N transistor.

Description : Compare P.N.P and N.P.N transistor.

Last Answer : Parameter PNP transistor NPN transistor Definition Two blocks of p- types semiconductors are separated by one thin block of n-type semiconductor. Transistor in which two ntype layer ... Positive Voltage  Emitter Terminal Collector Terminal Ground Signal High Low

What is race around condition in JK flip flop and how it can be eliminated?

Description : What is race around condition in JK flip flop and how it can be eliminated?

Last Answer : For the racing around to take place, it is necessary to have the enable input high along with J=K=1. As the enable input remains high for a long time in a JK latch, the problem of ... to zero. Hence the multiple toggling cannot take place. Thus the edge triggering avoids the race around condition.

Draw and explain self-basing of a transistor.

Description : Draw and explain self-basing of a transistor.

Last Answer : Transistor Biasing is the process of setting a transistors DC operating voltage or current conditions to the correct level so that any AC input signal can be amplified correctly by the transistor. ExplanationIt ... Applying KVL to o/p loop , Collector-emitter voltage, VCE = VCC − IC RC

Transistor operating configurations

Description : Transistor operating configurations

Last Answer : Transistor operating configurations

Define junction field effect transistor (JFET) and give an example.

Description : Define junction field effect transistor (JFET) and give an example.

Last Answer : Junction Field-Effect Transistor: It is a semiconductor device having three terminals, namely Gate, Drain and Source, in which the current flow is controlled by an electric field set up by an external voltage applied ... : i) n-channel JFET and ii) p-channel JFET Examples of JFET: BFW 10, BFW 11 

Define α & β and derive the relation between (α) &) (β) of transistor.

Description : Define α & β and derive the relation between (α) &) (β) of transistor.

Last Answer : α : The ratio of output collector current IC to input emitter current IE in the CB configuration is called current gain alpha (α).  β : The ratio of output collector current IC to the input base current IB in the CE configuration is ... ( 1/β) + 1  hence 1/ α = (1+β )/ β  Therefore, α = β /(1+β)

Define biasing of transistor

Description : Define biasing of transistor

Last Answer : Biasing of transistor is the process that makes the base emitter junction of transistor always forward biased and collector junction reverse biased for achieving the faithful amplification .

Compare between CB , CE & CC transistor configuration.

Description : Compare between CB , CE & CC transistor configuration.

Last Answer : Parameter CB CE CC I/P impedance Low Or 50Ω Medium Or 600Ωto 4kΩ High Or 1 MΩ Current Gain Less than or equal to 1 High Highest Voltage Gain Medium Medium Less ... k Ω to 50 k Ω Low Or 50 Ω Phase shift between input and output 0° 360° 0° 

Why transistor is called as bipolar device.

Description : Why transistor is called as bipolar device.

Last Answer : BJT is called bipolar device because in BJT current conduction takes place due to majority as well as minority charge carriers that is because of electrons as well as holes.

The necessary and sufficient condition for a rational function of, T(s) to be driving point impedance of an RC

Description : The necessary and sufficient condition for a rational function of, T(s) to be driving point impedance of an RC network is that all poles and zeros should be

Last Answer : The necessary and sufficient condition for a rational function of, T(s) to be driving point impedance of an RC network is that all poles and zeros should be simple and and lie on the negative axis in the s -plane

The condition for maximum efficiency for a D.C. generator is?

Last Answer : The condition for maximum efficiency for a D.C. generator is variable losses equal to constant losses.

The condition for maximum power in case of D.C. motor is?

Last Answer : (b) Clostridium butylicum Lipase Removal of oil stains

Draw construction of SCR using two transistor model. Explain its operation.

Description : Draw construction of SCR using two transistor model. Explain its operation.

Last Answer : Two Transistor Model of SCR or Thyristor

Describe thermal runaway of transistor and explain how it can be avoided.

Description : Describe thermal runaway of transistor and explain how it can be avoided.

Last Answer : Concept of thermal runaway:  1.We know that  IC = β IB + (1+ β) ICO  Where ICO is the leakage current and ICO is strongly dependent on temperature. 2. Leakage current approximately doubles for ...   Thermal runaway can be avoided by : 1) Using stabilization circuitry 2) Heat sink 

What is your definition of fair?

Description : What is your definition of fair?

Last Answer : Well it’s not fair that….. I have a brother and a sister and none of us get along and I’m always the easy going I will help you with anything kind of person and they always stab me in the back.

Draw the V-I characteristics of power transistor.

Description : Draw the V-I characteristics of power transistor. 

Last Answer : V-I characteristics of power transistor:

Define α and β of the transistor.

Description : Define α and β of the transistor. 

Last Answer : α: The ratio of collector current IC to emitter current IE for a constant collector to base voltage VCB in the CB configuration is called current gain alpha (α).   β : The ratio of collector ... a constant collector to emitter voltage VCE in the CE configuration is called current gain beta (β) .

List various transistor biasing methods.

Description : List various transistor biasing methods.

Last Answer : Types of biasing methods: i. Base bias (or fixed bias) ii. Base bias with emitter feedback. iii. Base bias with collector feedback iv. Voltage divider bias (or self bias) v. Emitter bias. 

What is the main use of a transistor?

Description : What is the main use of a transistor?

Last Answer : Main use of a transistor as amplifier and as switch.

Explain the construction and working of LVDT accelerometer with the help of diagram.

Description : Explain the construction and working of LVDT accelerometer with the help of diagram.

Last Answer : Explanation:* The LVDT accelerometer consists of one primary and two secondary windings which are placed on either side of central code. The two ends of the core are connected with ... in the output terminal. This output voltage is directly proportional to the vibration or acceleration. 

Explain with neat diagram the working of photo-voltaic cell.

Description : Explain with neat diagram the working of photo-voltaic cell. 

Last Answer : Diagram the working of photo-voltaic cell: Working:- Solar cell operates on principle of Photo-voltaic effect    Solar cell works in following steps: The solar cell is composed ... . When you connect loads such as a light bulb, electric current flows between the two electrodes.  

Explain the working of Hydro power station with schematic layout.

Description : Explain the working of Hydro power station with schematic layout. 

Last Answer : Working of Hydro- Electric Power Plant: Water stored at high level by constructing dam across river. This stored water has potential energy. This stored water is passed to run the water ... energy and Alternator is coupled to water turbine which converts mechanical energy into electrical energy. 

Explain the working of pump storage plant and also state its advantages.

Description : Explain the working of pump storage plant and also state its advantages. 

Last Answer : Working of Pumped storage hydroelectric power plant :-  It consists of head water pond (reservoir) and tail water pond by constructing a dam at tail race path.  Tail water pond and ... install as well as spinning reserve capacity of TPP as it provides additional power during peak load period.

Explain working of superheater and condenser.

Description : Explain working of superheater and condenser. 

Last Answer : Working of Super heater:  Super heater consist of group of tubes. Tubes are heated by absorbing temperature of flue gases passed over it . Superheated steam' is meant that steam which ... condensate is reused in boiler. This type of condenser is used for high capacity thermal power plant. 

Explain working of pumped storage plant.

Description : Explain working of pumped storage plant.

Last Answer : Working of pumped storage hydroelectric power plant:-  It consists of head water pond (reservoir) and tail water pond by constructing a dam at tail race path. Tail water pond and head water pond ... as centrifugal pump. Raising the water from tail water pond to head water pond through penstock.

Explain working of fast breeder reactor.

Description : Explain working of fast breeder reactor.

Last Answer : Fast Breeder Reactor (FBR):  A fast breeder reactor produces heat and at the same time converts fertile material into fissionable material. The central portion of this reactor is a stainless ... or thermal neutrons. In fact no moderator is present at all to slow down the fast neutrons. 

With neat diagram, explain the working of clip-on ammeter.

Description : With neat diagram, explain the working of clip-on ammeter.

Last Answer : Working of Clip on Ammeter: Clip on ammeters are used to measure the high current flowing through bus bar, cable or fuse holders, which act as primary. It consists of split core current ... then clipped over the current carrying conductor. The dial will record the current directly. 

Explain construction & working of attraction type M.I. instrument with neat diagram.

Description : Explain construction & working of attraction type M.I. instrument with neat diagram.

Last Answer : 1. Moving element: a small piece of soft iron in the form of a vane or rod.  2. In Attracted type a cylindrical coil or solenoid which is kept fixed. An oval-shaped soft-iron piece are ...   9. When = the pointer will be stable & we can get correct reading of the electrical quantity

Explain working of Weston type frequency meter.

Description : Explain working of Weston type frequency meter.

Last Answer : Weston Type Frequency Meter: There are two fixed coils marked as A and B. Each coil divided into two equal parts and are fixed such that their magnetic axis are perpendicular to each ... leading to deflections in either direction depending on the currents there in, due to changed impedances.

Explain construction & working of electrodynamometer type wattmeter.

Description : Explain construction & working of electrodynamometer type wattmeter.

Last Answer : Electrodynamometer Type Wattmeter:  Construction: It essentially consists of the fixed and moving coil. The fixed coil is split into two equal parts which are placed close together and parallel to each other. ... hence these instruments can be used for measurement of A.C. & D.C. power.

Draw symbol of LED and explain it’s working principle.

Description : Draw symbol of LED and explain it’s working principle.

Last Answer : Construction of LED: The basic structure of LED is shown in fig.(a). The active region exists between the p and n regions. The light emerges from the active side in all the directions when electron hole-pairs ... fig.(c). In this way an LED emits light. This is the principle of operation of LED.

State the working principle of gears and give its applications.

Description : State the working principle of gears and give its applications.

Last Answer : Working Principle:  Gears are mechanical elements which transmit motion by means of successively engaging teeth.  Gears are used to transmit motion from one shaft to another or between ... Agricultural equipment.  Industrial construction.  Mining equipment.  Automotive equipment.

Describe the procedure for working of paging system.

Description : Describe the procedure for working of paging system.

Last Answer : Pager is a Simplex Communication Device. Paging Systems are communication systems that send messages to a subscriber. Message can be numeric or alphanumeric. Paging Systems are used to notify a subscriber ... message is sent by sender to his pager and the message will be displayed in the LCD.

Describe the working principle of photoelectric pickup type tacho-generator.

Description : Describe the working principle of photoelectric pickup type tacho-generator.

Last Answer : Working: Working principle: The light passes through the holes available on the rotating disc with a specific interval, depends on the angular speed of disc having equidistant holes. The frequency of this light pulses ... by N=f/HS  N=speed  f=frequency  Hs=holes on the disc

Draw and describe working of electronic energy meter.

Description : Draw and describe working of electronic energy meter.

Last Answer : working of electronic energy meter:- 1. CT reduces current to reasonable value for current scaling network. 2. Voltage & current scaling networks reduce proportionally the voltage & ... The ADC converts the square wave frequency analog output to display the energy in watthour. 

Describe with working of LCR meter for measurement of inductance.

Description : Describe with working of LCR meter for measurement of inductance. 

Last Answer : working of LCR:- A LCR meter (Inductance (L), Capacitance (C), and Resistance (R) test equipment used to measure the inductance, capacitance and, resistance of a component. It works on the ... in parallel (as would be encountered in measuring a capacitor with a leaky dielectric) [Q setting ] 

State working principle of PMMC instrument.

Description : State working principle of PMMC instrument.

Last Answer : Working Principle of PMMC Instrument: When current carrying conductor is placed in a constant magnetic field, it experiences a force proportional to the current and produces proportional deflection torque. 

The effective resistance of an iron-cored choke working on ordinary supply frequency...

Description : The effective resistance of an iron-cored choke working on ordinary supply frequency is more than its true resistance because of?

Last Answer : The effective resistance of an iron-cored choke working on ordinary supply frequency is more than its true resistance because of iron loss in core.

Explain the working principle of induction motor.

Description : Explain the working principle of induction motor. 

Last Answer : Working principle of induction motor: * When the motor is excited with three-phase supply, three-phase stator winding carries three-phase currents & produces a rotating magnetic field of constant magnitude and ... , which tend to move the rotor in the same direction as the rotating magnetic field. 

Explain working of static AC circuit breaker.

Description : Explain working of static AC circuit breaker. 

Last Answer : Static AC Circuit breaker: The circuit configuration of static AC circuit breaker using SCR is shown in the figure. When switch S' is closed, the SCRs T1 and T2 are fired in positive ... non-availability of gate current. Thus the maximum time delay for breaking the circuit is one half-cycle.

Explain with neat sketch the working principle of MIG.

Description : Explain with neat sketch the working principle of MIG.

Last Answer : In metal-arc inert gas welding the Weld area is shielded by an effectively inert atmosphere of argon, helium, carbon dioxide, or various other gas mixtures . The consumable bare Wire is fed automatically ... of the molten-weld puddle. Multiple-weld layers can be deposited at the joint. 

Explain construction and working of AC servomotor.

Description : Explain construction and working of AC servomotor.

Last Answer : Construction of AC Servo Motor: AC servo motor is mainly composed of a stator and a rotor. Laminated stator core is usually made of silicon steel. Two phase windings are placed in the stator slots at 90 degree ... on rotor. Due to the force or torque acting on the rotor, it is set in motion. 

Explain the working of Neon sign tube with diagram.

Description : Explain the working of Neon sign tube with diagram.

Last Answer : Neon sign tube: The construction & circuit diagram for neon tube is as shown in fig. Basically neon tube is used for advertisement or decoration purpose. The maximum length of tube is ... the HT transformer must be earthed separately. * Caution notice of danger board is required.

Explain the working of HPMV Lamp with neat diagram.

Description : Explain the working of HPMV Lamp with neat diagram.

Last Answer : High-pressure Mercury-Vapour Lamp (HPMVL):  Working:  * Whenever 1-ph, 230V, AC Supply is provided to the discharge tube of MVL, initially the current flows from Phase to the choke to ... : The function of power factor improvement capacitor is to improve the power factor from 0.5 to 0.95.

Explain working of AC circuit breaker using SCR with circuit diagram.

Description : Explain working of AC circuit breaker using SCR with circuit diagram.

Last Answer : AC Circuit Breaker:  The circuit configuration of static AC circuit breaker using SCR is shown in the figure. When switch S' is closed, the SCRs T1 and T2 are fired in positive ... to non-availability of gate current. Thus the maximum time delay for breaking the circuit is one half-cycle.

Explain construction and working principle of single phase transformer.

Description : Explain construction and working principle of single phase transformer.

Last Answer : A single phase transformers is an electrical device that accepts single-phase AC power and outputs single-phase AC. PRINCIPLE... The single-phase transformer works on the principle of ... and secondary windings. Thin steel laminations shall be employed to prevent power losses from the core.

explain the working of single phase induction motor.

Description : explain the working of single phase induction motor.

Last Answer : Stator has two winding namely main winding and auxiliary winding.when single phase ac supply is given to the motor,its produces alternating field.this field cut by a cage rotor.so some emf ... due to this emf,rotor flux produced.the interaction between two fluxes produce torque.so rotor rotates.

How to Lose Weight Without Working Out

Description : How to Lose Weight Without Working Out

Last Answer : How to Lose Weight Without Working Out Weight loss is a major concern among many people. Whether a person is obese or just wants to shed a few extra pounds, keeping fit and trim is an important ... still lose excess pounds with just a few activities that don't involve a lot of sweating and toning.

State working principle of alternator. State the meaning self and separate excitation.

Description : State working principle of alternator. State the meaning self and separate excitation. 

Last Answer : Working principle of alternator: When a conductor is moved in magnetic field or a magnetic field moved with respect to conductor, according to Faraday's law of electromagnetic induction, the conductor ... like battery or shaft-mounted exciter, then the excitation is said to be separate excitation.