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Why FET called current controlled device?
BJT is a current controlled device because its output current is dependent upon the current in the base while for FET it is controlled by the voltage at the gate terminal of the transistor. BJT is a current controlled device because its base current is not zero while for a FET the gate current is zero
What is bjt and jfet?
BJT is Bipolar junction transistor FET is Field effect Transistor It is a current controlled device It is voltage controlled device
Why common collector amplifier current gain is equal to beta?
Actually the current gain is equal to Beta+1, not Beta. The current from/into the emitter is the sum of the current into/from the collector and base. Of course this assumes linear operation.For a proof: Ie + Ib + Ic = 0Ic = Beta * IbIe + Ib + Beta * Ib = 0Ie + (Beta + 1) * Ib = 0Ie = -(Beta + 1) * Ib
When the forward saturation in Bipolar junction transistor occurs?
Forward saturation in a BJT occurs when the ratio of collecter-emitter current and base-emitter current reaches hFe or dc beta. A that point, the BJT is no longer operating in linear mode.
In bjt small signal analysis in emitter stablization bias the circuit which have re unbypassed when trying to get zb the impedance why you divided vi by ib although that that both resistances beta r?
//you tell us and we'll both knowassuming that you have used h-parameter analysis for this ...Vb contains the Ib and the Ie terms which can be expressed ad Ie=(1+Hfe)Ibthen we haveVb=Hie*Ib + Re*Ie=Hie*Ib + Re(1+Hfe)Ib=Ib(Hie+(1+Hfe) Re)then we can findRi as Vb/Ib= Hie+(1+Hfe)*Rehope that helps....
Why bjt is called current controlled current device?
Because the operation of the transistor is determined by the current at the base. the principle equations of BJT operation are: Ic = h*Ib ,and Ie=Ib+Ic thus device operation is controlled by the input current.
Why FET called current controlled device?
BJT is a current controlled device because its output current is dependent upon the current in the base while for FET it is controlled by the voltage at the gate terminal of the transistor. BJT is a current controlled device because its base current is not zero while for a FET the gate current is zero
Why bjt is bipolar?
Bjt is bipolar because in bjt the conduction of current is due to the electrons as well as holes
What are the example current controlled device?
Bipolar junction transistor(BJT)
The current amplification factor adc is given by?
IC/IB where IC is Collector Current and IB is Base Current
Calculate the DC base current of a transistor circuit if the DC collector current is 4.9mA and the DC emitter current is 5mA?
Emitter current can be summed up by the formula: IE = IC+ IB Where IE = Emitter Current, IC = Collector Current, and IB = Base Current So simply take IE - IC and you'll get an IB of about 100uA. (5mA-4mA = .1mA or 100uA) Also, remember that IB controls IC and IE, not the other way around. You can also determine IB if Beta is known by the formula: IC = IB * Beta Which can be manipulated to equal IB = IC/Beta Hope this was helpful.
What is bjt and jfet?
BJT is Bipolar junction transistor FET is Field effect Transistor It is a current controlled device It is voltage controlled device
Why common collector amplifier current gain is equal to beta?
Actually the current gain is equal to Beta+1, not Beta. The current from/into the emitter is the sum of the current into/from the collector and base. Of course this assumes linear operation.For a proof: Ie + Ib + Ic = 0Ic = Beta * IbIe + Ib + Beta * Ib = 0Ie + (Beta + 1) * Ib = 0Ie = -(Beta + 1) * Ib
How to calculate the current gain in darlington pair?
start at Ic'= Ic1+Ic2 Ib'=Ib1 Ic1=B1*Ib' Ie1=Ib2=Ib'(B1+1)=Ib'B1 + Ib' Ic' = Ib'*B1 + Ic2 Ic2= B2(Ib'B1+Ib') Ic' = Ib'B1 + Ib'B1B2 + Ib'B2 divide by Ib' Ic'/Ib'= current gain =B'=B1+B2+B1B2 note: calculations without resistance
What are current controllable devices?
BJT is a example for current controll device. And JFET is a voltage controlled device.
What is the difference between jfet and bjt?
FET's (field effect transistors) are unipolar devices because unlike BJT's that use both electron and hole current, they operate only with one type of charge carrier. BJT is a current-controlled device; that is the base current controls the amount of collector current. FET is a voltage-controlled device, where voltave between two of the terminals (gate and source) controls the current through the device. BJT's have a low input impedance ( ~1k -3k ohms), while FET's have a very high input impedance (~10^11 ohms). Consequently FET's have a lower power consumption. BJT's produce more noise than FET's . FET's have a slower switching speed . BJT's are subject to thermal runway while FET's are immune to this problem. BJT's have a higher cutoff frequencey and a higher maximum current then FET's. FET's are easy to fabricate in large scale and have higher element density the BJT's.
How do you calculate the current gain of a transistor?
Bipolar transistor current gain is also called "Beta," or the h-parameter "hfe." beta = current_out / current_in The beta of a BJT is mostly determined by the thickness of the Base region, and by the excess doping in the Emitter relative to the Base. A thin Base and a heavily-doped Emitter leads to a high value for current gain. In a BJT, beta = Ic / Ib In a FET, beta is usually taken as infinity, since no current flows in or out of the gate. Beta is an impirical number. It means nothing unless the Ic is known or the load. It can have a beta from 1000 to 10 it all depends on the load.
