Comparison of BJT and FET

2 Answers

Answer :

Parameter
BJT
FET
Control parameter
Current control device
Voltage control device
Input junction
Always forward biased
Always reversed biased 
charge carriers
Electrons and holes both are carrying current
Either electrons or holes carry currents.
Noise
More noise
less noise
Terminals
Emitter, base collector
Source, Gate Drain

Answer :

FET
BJT
It is unipolar device i.e. current in the device is carried either by electrons or holes
It is bipolar device i.e. current in the device is carried either by both electrons & holes
It is a voltage controlled device i.e. voltage at the gate (or drain) terminal controls amount of current flowing through the device.
It is a current controlled device i.e. the base current controls the amount of collector current. 
It has a negative temperature coefficient at high current levels. It means that current decreases as temperature increases.
It has a positive temperature coefficient at high current levels. It means that current increases as temperature increases.
It has relatively lower gain bandwidth product as compared to BJT.
It has relatively higher gain bandwidth product as compared to FET.
It is less noisy.
It is comparatively more noisy.
It is relatively immune to radiation.
It is susceptible to radiation

Related questions

Description : Comparison of three configuration of BJT

Last Answer : Parameter Common Base(CB) Common Emitter (CE) Common collector (CC) Input terminal  Emitter Base Base Common terminal Base Emitter Collector Output terminal Collector Collector Emitter Gain factor Alpha(Ic/Ie) Beta(Ic/Ib) Gamma(Ie/Ib)

Description : Draw circuit diagram of two stage RC coupled amplifier using BJT

Last Answer : BJT - To amplify input signal. R1 & R2 = Biasing resistor to provide DC biasing voltage RE = Emitter resistor to control gain RL = Load resistor to carry load current Cin = Cout = Coupling capacitors to block DC CE = emitter bypass resistor

Description : Draw symbol of NPN transistor and state three configurations of transistor (BJT)

Last Answer : Configuration - Common Emitter Common Collector Common Base

Description : why the bjt is known as current controlled device and fet is known as voltage controlled device ?

Last Answer : Ans- 1. In BJT because of the current the output will vary. 2. Where as in FET by means of Voltage the output is varied.

Description : Compare BJT with FET

Last Answer : FET BJT It is unipolar device i.e. current in the device is carried either by electrons or holes It is bipolar device i.e. current in the device is carried either by ... from minority- carrier storage effects & therefore has lower switching speeds & cut-off frequencies. 

Description : Compare between BJT and FET on the basis of (i) Biolar/Unipolar (ii) Tharmal Runaway (iii) Noise (iv) Applications

Last Answer : Parameter BJT FET Bipolar/Unipolar It is bipolar device i.e. current in this device is carried by electrons and holes. It is unipolar device i.e. current ... in oscilloscopes, electronic voltmeters and other measuring and testing equipment because of their high input impedance.

Description : An FET is a better chopper than a BJT because it has (A) lower offset voltage (B) higher series ON resistance (C) lower input current (D) higher input impedance

Last Answer : An FET is a better chopper than a BJT because it has lower offset voltage

Description : What is the difference between BJT and FET?

Last Answer : BJT  is  a  current  opperated   transistor  while  FET   is  a  field   opperated  transistor.

Description : Is the input impedance of MOSFET more than BJT and FET?

Last Answer : Yes, the input impedance of MOSFET more than BJT and FET.

Description : Piezo-electric effect

Last Answer : Piezoelectric Effect is the ability of certain materials to generate an electric charge in response to applied mechanical stress. The word Piezoelectric is derived from the Greek piezein, which means to squeeze or ... Storage Temperature Range: -55 to + 125°C Insulation Resistance: 500 M ohms

Description : Shift Register

Last Answer : Shift Register:- Shift Register is a group of flipflops used to shift data from one side to other side or to convert serial data into parallel or vice versa. Shift registers are of following types  i) ... iii) Parallel in serial out(PISO) iv) Parallel in parallel out(PIPO)

Description : Selection Criteria of PLC

Last Answer : Selection criteria :- To select PLC for any particular application following points are to be considered. a) Type of PLC: Analog or Digital b) Number of inputs and outputs to PLC c) Operating voltage ... Type of memory of PLC g) Type of programming h) Reliability of PLC i) Flexibility of PLC

Description : Function of OR Gate its logical symbol and truth table.

Last Answer : Function: - OR gate is used to perform logical addition. So used in adder subtractor and logic circuits where logical Oring is required. Used to implement SOP form equations. Also used in PLA logic. Logical symbol of OR gate :- Truth table:- 

Description : List various elements of mechatronic system and state applications.

Last Answer : Elements Sensors. Actuators (Hydraulics, Phnumetics) PLC, Micro controllers. Electrical Motors. Mechanical Couplings, Assembly & Gears. Control Panel. Applications ... washer and washing machines. automatic air conditioning systems unmanned aerial vehicles and automatic pilots. 

Description : Define transducer. State factors which are considered while selecting transducer for a particular application.

Last Answer : Transducer - It converts one form of signal into another form. A transducer is a device that is used to convert a physical quantity into its corresponding electrical signal. ... compatibility : The transducer should maintain input and output characteristic for the selected environmental condition.

Description : Define multiplexer. Draw logical symbol of 4:1 multiplexer with truth table and output logical equation

Last Answer : Multiplexer - it is a combinational circuit which selects one input from several inputs and connects it to the output.  It is a circuit which has N-input and single output is called as multiplexer.

Description : State the need of multistage amplifier. List the types of multistage amplifier and give two advantages of each type. 

Last Answer : Need of multistage amplifier: The voltage (or power) gain, obtained from a single stage small signal amplifier, is limited. Therefore, it is not sufficient for all practical applications. Therefore, ... use more than one stage of amplification. Such an amplifier is called a MULTISTAGE AMPLIFIER .

Description : Compare microprocessor and microcontroller

Last Answer : Application Microprocessor - Computer, Mobile phone, calculator Microcontroller - washing machine, microwave oven Microprocessor Microcontroller Do not have inbuilt RAM or ROM ... access Less multifunction pins on the IC Many multifunction pins on the IC

Description : Draw a labelled pin diagram of IC-555 and state function of each pin

Last Answer : Pin Name Purpose 1 GND Ground reference voltage, low level (0 V)  2 TRIG The OUT pin goes high and a timing interval starts when this input falls below 1/2 of ... 8 Vcc Positive supply voltage, which is usually between 3 and 15 V depending on the variation.

Description : Compare LED and Photo diode 

Last Answer : Parameters LED (Light Emitting Diode) Photodiode Definition Two terminal device which converts electrical energy into light energy.  Two Terminal Device which converts light energy into ... and Numeric display etc. Switching, high speed counting, ac coupled signaling etc.

Description : Name the circuit used in rectifier to minimize ripple. List the types of this circuit with simple circuit diagram.

Last Answer : Rectifier filter is an electronic circuit that removes ripple or unwanted AC signal components from the output of a Rectifier. Types - (a) Series Inductor filter (d) Shunt capacitor filter (b) L-C type filter (e) Π - type filter

Description : Draw simple block diagram of CNC machine and describe in short.

Last Answer : (i) Input Devices: These are the devices which are used to input the part program in the CNC machine. There are three commonly used input devices and these are punch tape reader, magnetic tape ... Unit: A monitor is used to display the programs, commands and other useful data of CNC machine.

Description : Describe how Op-Amp is used as adder using circuit diagram and output voltage equation.

Last Answer : Summing Amplifier Circuit In this simple summing amplifier circuit, the output voltage, ( Vout ) now becomes proportional to the sum of the input voltages, V1, V2, V3, etc. Then we can ... to the non-inverting input of the op-amp, it will produce the positive sum of the input voltages.

Description : Define rectifier. Draw circuit diagram and input-output waveforms of bridge type full wave rectifier 

Last Answer : Rectifier - This circuit convert AC signal into DC.

Description : List various types of CNC machine

Last Answer : • CNC Plasma Cutting Machine. • CNC Laser Cutting Machine. • CNC Milling Machine. • CNC Router Machine. • CNC Lathe Machine.

Description : State important specification parameters of ADC

Last Answer : Accuracy Resolution Linearity Conversion time Settling time stability

Description : Give examples of : (i) Electrical transducer (ii) Mechanical Transducer

Last Answer : (i) Electrical transducer Voltage measurement Temperature measurement Strain measurement (ii) Mechanical Transducer Pressure measurement Force measurement Velocity measurement

Description : Draw pin diagram of Op-Amp IC-741.

Last Answer : Pin diagram of Op-Amp IC-741 :

Description : Define counter. State four applications of counter.

Last Answer : Counter - The circuit which counts number of clock pulses is called as counter. Applications - Processor Real time clock Calculator Batch counter

Description : Why NAND and NOR gate are called as universal gate? Draw AND gate using NAND gate only. 

Last Answer : Universal gate - All basic gates functionality can be implemented using NAND and NOR gate hence these gates are called as universal gates.  AND gate using NAND gate

Description : Give the speciality of zener diode. State its 2-3 applications

Last Answer : Speciality - This diode can keep breakdown voltage constant across it. It is used in reverse bias. Applications - Zener diodes voltage regulation as reference elements surge suppressors switching applications clipper circuits.

Description : What is the full form of FET ?

Last Answer : The full name of FET is Field effect Transistor

Description : my adopted son has adhd and is Bipolar mixed and I have had him in and out of physc wards since he was 12, now he is 16,and failing 9th grade and apparently doesnt care.talking doesnt work taking things away ie, tv,phone privaleges,etc , Im also fet up ?

Last Answer : Bipolar disorder is a very serious MEDICAL condition, and cannot be treated by taking away phone and TV privileges. Your son is in serious need of help; seek out a well-regarded specialist A.S.A.P.

Description : Why is input impedance of the FET very high?

Last Answer : BECAUSE its input circuit (gate to source) is reverse biased and input gate current is very small.

Description : An FET has a gate source bias of 2 V. The ac input signal is ± 1.2 V. The class of operation is A) A B) B C) C D) AB

Last Answer : D) AB

Description : Applying a reverse bias to the gate of an FET has what effect?

Last Answer : Source-to-drain resistance increases.

Description : What is the key to FET operation?

Last Answer : Effective cross-sectional area of the channel.

Description : The base of a transistor serves a purpose similar to what element of the FET

Last Answer : Gate.

Description : The FET and the vacuum tube have what in common?

Last Answer : Voltage controls conduction.

Description : What is one of the primary advantages of the FET when compared to the bipolar transistor?

Last Answer : High input impedance.

Description : State the classifications of FET devices.

Last Answer : FET is classified as 1. Junction Field Effect Transistor (JFET) 2. Metal oxide semiconductor family (MOS).

Description : In a transistor, the conventional current flows from base to emitter. The transistor is (a) NPN (b) PNP (c) FET (d) None of these

Last Answer : (a) NPN

Description : A semiconductor device made up of a single p-n Junction is called a: w) transistor x) diode y) Fet z) integrated circuit

Last Answer : ANSWER: X -- DIODE

Description : State any two applications of FET.

Last Answer : Applications of FET : As input amplifiers in oscilloscopes, electronic voltmeters and other measuring and testing equipment because high input impedance reduces loading effect to the minimum. As Constant ... Used as Analog switch. As a Voltage Variable Resistor (VVR) in operational amplifiers. 

Description : State and explain the working principle of FET amplifier and list its applications.

Last Answer : Operation of FET amplifier: When small a.c. signal is applied to the gate, it produces variation in the gate to source voltage. This results in variation in the drain current. As ... input voltage.  Application: Buffer amplifier Low noise amplifier Cascade amplifier Chopper amplifier

Description : Draw the drain characteristics of p-channel FET and explain.

Last Answer : Drain characteristics:- As VDS is increased from zero as shown , ID will increased proportionally through the p channel. In this region the channel resistance is constants because the depletion region is ... the depletion layer. (i.e. channel width zero) is called cutoff voltage or VGS(off).

Description : Define with respect to FET:- (i) Static drain resistance (ii) Dynamic resistance (iii) Trans conductance (iv) Pinch-off voltage

Last Answer : (i) Static drain resistance- It is the ratio of drain source voltage (ΔVDS) to the drain current (ID) at constant gate-source voltage. It can be expressed as, Rd = (VDS)/(ID) at ... of charge carrier and the value of drain current reaches its constant saturation value is called pinch off voltage.

Description : Sketch circuit diagram of common source FET Amplifier. State working principle of it.

Last Answer : Working: -  * When small a.c. signal is applied to the gate, it produces variation in the gate to source voltage. This produces variation in the drain current. As the gate to source ... and we get amplification. Thus the AC output voltage VDS is 180º out of phase with AC input voltage.

Description :  construction of P-channel J-FET.

Last Answer : Construction of P-channel J-FET : The construction diagram of P channel junction field effect transistor (JFET) is shown in above figure. It consist of a P type silicon ... enter the semiconductor bar and Source (S) is a terminal through which the electrons leave the semiconductor. 

Description : Explain N-channel J-FET with its transfer characteristics.

Last Answer : Working of Channel JFET: Working: 1. The application of negative gate voltage and positive drain voltage with respect to source, reverse biases the gate- source junction of an N-channel JFET. 2. When a ... symbol VP or VGS(OFF) . The value of VP is negative for N-channel JFET.