Why BJT is a current control device?

Why BJT is a current control device?
by

1 Answer

Answer :

BJT have three terminal emitter, base and collector. The collector current is the output current. The collector current (Ic) is controlled by base current hence BJT is called current controlled device.

by

Related questions

why bjt is called current controlled device?

Last Answer : In  BJT  there  is  movement  of   electrons  and  holes   accros  the  junctions  which  is  basicaly  current  flow.

is bjt a voltage controlled device ?

Last Answer : No, BJT is a current controlled device .

Is BJT current controlled or voltage controlled?

Last Answer : BJT is current controlled device.

Power BJT is a current controlled device. Why?

Description : Power BJT is a current controlled device. Why?

Last Answer : Because the output (collector) current can be controlled by base current.

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

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.

An FET is a better chopper than a BJT because it has

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

What is a BJT?

Description : What is a BJT?

Last Answer : Bipolar Junction Transistor (BJT): BJT is a Bipolar device. (Uses both electrons and holes charge carrier for current conduction) Two Junctions (Emitter junction & collector ... mode (Current amplification) Cutoff mode (Open switch) Saturation mode (Close switch)

Is BJT unipolar or bipolar Why?

Description : Is BJT unipolar or bipolar Why?

Last Answer : Bipolar Junction Transistor (BJT) is a bipolar device because current is carried by both holes and electrons hence it is called bipolar.

is IGBT costlier than BJT and MOSFET?

Last Answer : Yes IGBT is costlier than BJT and MOSFET.

does the BJT have internal capacitance?

Last Answer : Yes BJT have internal capacitances.

in which region BJT act as a switch?

Last Answer : BJT act as switch in saturation and  cutoff region ( ON state in saturation region and OFF state in cut-off region )

in which BJT operating region both the junctions are reverse biased?

Last Answer : In cut-off region of BJT both the emitter-base junction and collector-base junction are reverse biased.

in which region BJT act as amplifier?

Last Answer : Active region of BJT act as amplifier.

what are the three operating regions of BJT?

Last Answer : Active , Saturation , Cut-off region of operations in BJT.

Does BJT have second breakdown problem?

Last Answer : Yes BJT have second breakdown problem.

BJT have how many terminals?

Last Answer : BJT have three terminals Base, emitter and collector.

when bjt is in cutoff ?

Last Answer : When Q-point is at cut off region means it is just above the horizontal axis VCE

what is bjt biasing?

Last Answer : The proper flow of zero signal collector current and the maintenance of the proper collector emmiter voltage during passage of single called as transistor biasing

bjt what is beta ?

Last Answer : Beta is the current gain which is the ratio of collector current to base current.

bjt is active or passive?

Last Answer : BJT control the flow of electron so it is a active device.

what does bjt stand for?

Last Answer : Bipolar junction transistor

what are bjt amplifiers used for?

Last Answer : Transformer coupled amplifiers Direct coupled amplifiers Multistage amplifiers Darlington amplifiers Emmiter follower

what are bjt transistors?

Description : what are bjt transistors?

Last Answer : Bjt transistor is a type of transistor which  uses both electrons and hole charge carrier.bjts are used as switches and amplifiers.They amplify currents.

Which is the most suitable power device for high frequency ( more 100 kHz) switching application? a) Power MOSFET b) BJT c) SCR d) UJT

Description : Which is the most suitable power device for high frequency ( more 100 kHz) switching application? a) Power MOSFET b) BJT c) SCR d) UJT

Last Answer : Ans: Power MOSFET

A modern power semiconductor device IGBT is combines the characteristics of a) BJT and MOSFET b) FCT and GTO c) SCR and MOSFET d) SCR and BJT

Description : A modern power semiconductor device IGBT is combines the characteristics of a) BJT and MOSFET b) FCT and GTO c) SCR and MOSFET d) SCR and BJT

Last Answer : Ans: BJT and MOSFET

A bipolar junction transistor (BJT) is used as a power control switch by biasing it in the cut-off region

Description : A bipolar junction transistor (BJT) is used as a power control switch by biasing it in the cut-off region (OFF state) or in the saturation region (ON state). In the ON state, for ... base-collector junction is reverse biased (D) both the base-emitter and base-collector junctions are forward biased

Last Answer : A BJT is as a power control switch by biasing it in cut-off region (OFF state) or in the saturation region (ON state). In  ON state, for BJT both the base-emitter and base- collector junctions are forward biased

Identify type of BJT configuration having following features : (i) BJT configuration having the least current gain. (ii) KIT configuration called as voltage follower. (iii) BJT configuration having current gain less than one. (iv) BJT configuration suitable for impedance matching. (v) BIT configuration suitable for voltage amplification. (vi) BJT configuration having the least output impedance.

Description : Identify type of BJT configuration having following features : (i) BJT configuration having the least current gain. (ii) KIT configuration called as voltage follower. (iii) BJT ... configuration suitable for voltage amplification. (vi) BJT configuration having the least output impedance.  

Last Answer : (i) BJT configuration having the least current gain : Common Base Configuration  (ii) KIT configuration called as voltage follower: Common Collector Configuration  (iii) BJT ... Emitter Configuration  (vi) BJT configuration having the least output impedance: Common Collector Configuration

Compare BJT common base configuration with common collector configuration on the basis of (i) Current gain (ii) Voltage gain (iii) Input impedance (iv) Output impedance

Description : Compare BJT common base configuration with common collector configuration on the basis of (i) Current gain (ii) Voltage gain (iii) Input impedance (iv) Output impedance

Last Answer : Parameter Common Base Common Collector Current gain Low (About 1) High (1+β) Voltage gain High 1  Input impedance  Low High Output impedance High Low

If the base current of a BJT is 250 µA and emitter current is 15 mA, then the common base current gain will be

Description :  If the base current of a BJT is 250 µA and emitter current is 15 mA, then the common base current gain will be A) 0.98 B) 0.41 C) 59 D) 55  

Last Answer :  If the base current of a BJT is 250 µA and emitter current is 15 mA, then the common base current gain will be 0.98 

The seven segment arrangement for numerical display on consoles, test meters and other applications can be either ________________. A. UJT or BJT B. BCD or OCD C. JFET or IGFET D. LED or LCD

Description : The seven segment arrangement for numerical display on consoles, test meters and other applications can be either ________________. A. UJT or BJT B. BCD or OCD C. JFET or IGFET D. LED or LCD

Last Answer : Answer: D

Draw the output characteristics of BJT in CE configuration and label various regions on it.

Description : Draw the output characteristics of BJT in CE configuration and label various regions on it.

Last Answer :  output characteristics of BJT in CE configuration 

State the applications of BJT.

Description : State the applications of BJT.

Last Answer : Applications of BJT: 1. As a switch 2. As an amplifier 3. As a multivibrator 4. As a oscillator 5. As a timer circuit 6. As a Logic circuits 7. Delay circuits

Draw the construction of BJT (NPN) and explain its working principle. State and explain different operating regions.

Description : Draw the construction of BJT (NPN) and explain its working principle. State and explain different operating regions.

Last Answer : Construction of BJT (NPN): Working of NPN Transistor : The circuit diagram of the NPN transistor is shown in the figure below. The forward biased is applied across the emitter-base ... Zero with input current is Zero transistor in cut off. In this region transistor act as open switch

Define the following with respect to BJT. (i) Input resistance (ii) Output resistance

Description : Define the following with respect to BJT. (i) Input resistance (ii) Output resistance

Last Answer : Input resistance: It is the ratio of small change in emitter -to-base voltage(∆VEB) to the resulting change in emitter current (∆IE) for a constant collector to base voltage(VCB) ... of BJT is ratio of voltage between output terminal and common terminal to current through output terminal. 

State 2 advantages of JFET over BJT.

Description : State 2 advantages of JFET over BJT.

Last Answer : Advantages of JFET over BJT: 1) High input impedance 2) Better thermal stability 3) Produce less noise 4) Smaller than BJT 5) Rugged in construction and simpler to fabricate 6) High degree of isolation between Input and Output. 

Name two types of BJT &draw their symbols.

Description : Name two types of BJT &draw their symbols. 

Last Answer : Two types of BJT: * NPN * PNP 

List the types of coupling used in BJT amplifier.

Description : List the types of coupling used in BJT amplifier. 

Last Answer : Types of coupling used in BJT amplifier: i. Resistance capacitance (RC)coupling ii. Impedance coupling iii. Transformer coupling iv. Direct coupling

Comparison of three configuration of BJT

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)

Comparison of BJT and FET

Description : Comparison of BJT and 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 both ... is comparatively more noisy. It is relatively immune to radiation. It is susceptible to radiation

Draw circuit diagram of two stage RC coupled amplifier using BJT

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

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

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

Last Answer : Configuration - Common Emitter Common Collector Common Base

List specification of BJT.

Description : List specification of BJT.

Last Answer : * The bipolar junction transistor (BJT) has small signal current gain, α (hfb). * Maximum collector current Ic (max). * Maximum collector to emitter voltage, VCE (max). * Collector to emitter ... . * Collector to emitter cut off voltage, VCEO. * Base emitter saturation voltage, VBE (sat).

State reason BJT is called as bipolar junction transistor.

Description : State reason BJT is called as bipolar junction transistor.

Last Answer : BJT is called bipolar junction transistor because in BJT current conduction takes place due to majority as well as minority charge carriers.

List configurations of BJT.

Description : List configurations of BJT. 

Last Answer : Configurations of BJT : 1) Common Base (CB) configuration 2) Common Emitter (CE) configuration 3) Common Collector (CC) configuration

State the need of biasing of BJT.

Description : State the need of biasing of BJT.

Last Answer : Need of biasing: The basic need of transistor biasing is to keep the base-emitter (B-E) junction properly forward biased and the collector-emitter (C-E) junction properly reverse biased ... transistor biasing is necessary for normal and proper operation of transistor to be used for amplification. 

Draw circuit diagram of voltage divider biasing list two advantages of voltage divider biasing of BJT.

Description : Draw circuit diagram of voltage divider biasing list two advantages of voltage divider biasing of BJT.

Last Answer : Two advantages of voltage divider biasing of BJT. 1. It is very simple method of transistor biasing. 2. The biasing conditions can be very easily set. 3. there is no loading of ... 5. The resistor RE introduces a negative feedback. So all the advantages of negative feedback are obtained. 

Compare BJT with FET

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. 

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

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.

In a BJT circuit a pnp transistor is replaced by npn transistor. To analyse the new circuit

Description : In a BJT circuit a pnp transistor is replaced by npn transistor. To analyse the new circuit (1) All calculations done earlier have to be repeated (2) Replace all calculated voltages by ... all calculated currents by reverse values (4) Replace all calculated voltages and currents by reverse values 

Last Answer : In a BJT circuit a pnp transistor is replaced by npn transistor. To analyse the new circuit  Replace all calculated voltages and currents by reverse values 

As compared to power MOSFET, a BJT has

Description : As compared to power MOSFET, a BJT has  (a) Lower switching losses but higher conduction losses (b) Higher switching losses and higher conduction losses (c) Higher switching losses but lower conduction losses (d) Lower switching losses and lower conduction losses. 

Last Answer : As compared to power MOSFET, a BJT has Higher switching losses but lower conduction losses