# why bjt is called current controlled device?

In bjt the movement of electrons and hole totally depend on current.
In  BJT  there  is  movement  of   electrons  and  holes   accros  the  junctions  which  is  basicaly  current  flow.

## Related questions

Answer : No, BJT is a current controlled device .

Answer : BJT is current controlled device.

Answer : No, IGBT is not the current controlled device. IGBT is a voltage controlled device. IGBT have combine qualities of MOSFET and BJT. The high switching speed of MOSFET and low conduction losses of BJT. Also, IGBT which stands for Insulated Gate Bipolar Transistor have high input impedance.

Description : A current controlled voltage source is equivalent to :  (A) series voltage feed -back amplifier (B) shunt current feed -back amplifier (C) shunt voltage feed -back amplifier (D) series current feed -back amplifier

Answer : A current controlled voltage source is equivalent to : shunt voltage feed -back amplifier

Description : A 3 -phase, fully controlled, converter is feeding power into a DC load at a constant current of 150 A, the rms value of the current flowing through each thyristor of the converter is

Answer : A 3 -phase, fully controlled, converter is feeding power into a DC load at a constant current of 150 A, the rms value of the current flowing through each thyristor of the converter is 150/√3

Description : When the firing angle a of a single-phase, fully controlled rectifier feeding constant direct current into a load is 30°, the displacement power factor of the rectifier is

Answer : When the firing angle a of a single-phase, fully controlled rectifier feeding constant direct current into a load is 30°, the displacement power factor of the rectifier is √3/2

Answer : The gravity controlled instrument has crowded scale because current is proportional to sine of deflection angle.

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

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

Answer : Thyristor can only be turned on by small gate pulse but it cannot be turn off by using gate hence thyristor is called semi controlled device.

Answer : MOSFET  are voltage controlled devices.

Answer : Because it has a higher switching frequency and heat tolerance.

Answer : ON state losses of IGBT is less as compared to MOSFET and BJT.

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

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

Description : What is a BJT?

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)

Answer : Yes IGBT is costlier than BJT and MOSFET.

Answer : Yes BJT have internal capacitances.

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

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

Answer : Active region of BJT act as amplifier.

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

Answer : Yes BJT have second breakdown problem.

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

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

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

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

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

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

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.

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

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

Description : Why BJT is a current control device?

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.

Description : State classification of Phase controlled rectifiers.

Answer : Classification of phase controlled rectifiers:

Description : Application one lamp controlled from two places

Answer : Application one lamp controlled from two places: 1. For Stair case wiring 2. Hospital Wiring ( For operating the lamp in room and nursing station) 3. Bedroom Lighting.

Description : Single-phase mid-point controlled rectifier with RL load

Answer : Single-phase mid-point controlled rectifier with RL load : The circuit configuration of single-phase midpoint controlled rectifier is shown in the figure. During positive half-cycle of ... some part of next positive half-cycle of voltage with reversed polarity can appear across load.

Description : Single-phase Midpoint controlled rectifier with Resistive load

Answer : Single-phase Midpoint controlled rectifier with Resistive load:  1) During positive half cycle of AC supply, a is positive with respect to b , this makes T1 forward biased and T2 is reverse ... voltage reverses the polarity and T2 is turned off. The operation is as shown in waveforms.

Description : Give the operation of single phase full wave bridge controlled converter with RL load with a neat diagram. Also draw its waveform.

Answer : Single phase fully control bridge converter with RL load: 1. During positive half cycle of input voltage, T1 and T2 are forward biased and during negative half cycle, T3 and T4 are forward biased. Therefore, T1-T2 ... cycle till the firing of next pair of SCRs as shown in the waveform.

Description : Draw a neat diagram of 1Ф half wave controlled converter with RL load. Give its operation.

Answer : Single phase fully controlled half wave converter:  The circuit diagram of single-phase half-wave controlled rectifier with RL load and without freewheeling diode is shown in Fig. (a). The SCR T is ... , when again pulse is applied, the SCR is turned on & the above cycle is repeated.

Description : How are nuclear reactors controlled? Explain two different methods in brief.

Answer : Nuclear reactor is controlled using control rods: Control rods are made up of very high neutron absorbing material like boron, cadmium. By adjusting height of control rods on reactor core ... of nuclear reaction will increase. Whereas by pushing control rod towards the core it will reduce.

Description : The speed of a three-phase induction motor is controlled by variable voltage variable frequency control (i.e. keeping V/f constant). As the frequency is reduced, the slip at maximum torque  (1) Decreases (2) Increases (3) Remains constant (4) None of the above

Answer : The speed of a three-phase induction motor is controlled by variable voltage variable frequency control (i.e. keeping V/f constant). As the frequency is reduced, the slip at maximum torque Increases

Description : A 230 V, 50 Hz phase controlled single-phase full-controlled SCR bridge converter draws 15 A constant dc current. If the source inductance is 3 mH, the drop in dc output voltage is (A) 4.5 V (B) 6.75 V (C) 9 V (D) 13.5 V

Answer : A 230 V, 50 Hz phase controlled single-phase full-controlled SCR bridge converter draws 15 A constant dc current. If the source inductance is 3 mH, the drop in dc output voltage is 9 V

Description : In voltage source converter based HVDC transmission system the active power is controlled by changing (A) phase angle of the converter ac input voltage (B) supply frequency of the converter ac input voltage (C) magnitude of the converter ac input voltage (D) DC voltage at the inverter terminals

Answer : In voltage source converter based HVDC transmission system the active power is controlled by changing phase angle of the converter ac input voltage

Description : For a 15-bus power system with 3 voltage controlled buses, the size of Jacobian matrix is

Answer : For a 15-bus power system with 3 voltage controlled buses, the size of Jacobian matrix is 25 x 25

Answer : The speed of a locomotive is controlled by gear box.

Description : How many servos can be controlled by Arduino?

Description : Chopper controlled DC motor

Answer : Chopper controlled DC motor

Description : State 2 advantages of JFET over BJT.

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.

Description : List specification of BJT.

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).

Description : List configurations of BJT.

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

Description : State the need of biasing of BJT.

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.

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