Table of Contents
- 1 Why emitter current is greater than collector current?
- 2 Why collector and emitter current is nearly equal in these transistors?
- 3 When the collector current in a transistor is zero the transistor is?
- 4 Why the thickness of base is smaller than emitter and collector?
- 5 Why is the collector of a BJT transistor of the largest size?
- 6 How can the base current of an emitter be reduced?
Why emitter current is greater than collector current?
The base contains more holes than electrons. As the direction of current is opposite to the flow of electrons we can understand that current from the emitter is conducted to the base and the collector. Hence, the collector current will always be slightly less than the emitter current.
Why collector and emitter current is nearly equal in these transistors?
In any configuration biased in the linear region, collector current is almost equal to emitter current. This is because of the large current gain of a bipolar transistor. So very little base current causes a very large collector to emitter current.
What is the relationship between collector current and emitter current?
What is the relationship between the base-emitter and collector-emitter voltages of a bipolar transistor? Generally, the current that flows from the emitter to the collector or vice versa is the base current times the DC current gain (hFE).
What is emitter current?
The emitter current, Ie, of a transistor is the amplified output current of a bipolar junction transistor.
When the collector current in a transistor is zero the transistor is?
Here the operating conditions of the transistor are zero input base current ( IB ), zero output collector current ( IC ) and maximum collector voltage ( VCE ) which results in a large depletion layer and no current flowing through the device. Therefore the transistor is switched “Fully-OFF”.
Why the thickness of base is smaller than emitter and collector?
The base region in a transistor is made very thin so that there is a better conduction of majority carriers from emitter to collector through base. The base region in a transistor is doped lightly so that the number density of majority carriers (electrons in p-n and holes in n-p-n transistor) is low.
Why is the emitter current greater than the collector current?
So very little base current causes a very large collector to emitter current. The base current and collector current combine and become the emitter current. But since the base current is anywhere from 1/20 to 1/300 of the collector current, emitter current is only very slightly greater than collector current.
What is the difference between BJT base junction and emitter junction?
(1) A BJT base junction is designed lightly doped, compared to emitter and collector junctions. The much heavier doping concentration of the emitter makes the emitter current much larger than the base current when the emitter-base junction is forward biased. Please, note that, for an active mode operation, the B-E diode is forward biased.
Why is the collector of a BJT transistor of the largest size?
The reason behind the collector is having the largest size in BJT is because it is the region which receives the majority of the current carriers, which for a npn transistor are electrons and for pnp transistors are holes. The collector receives the current carriers from the base and the emitter regions of the transistor.
How can the base current of an emitter be reduced?
(2) The base current is further reduced by making the base junction thinner while volumetrically completely enclosing the emitter. This increases the emitter to collector current at the same base current. Or it decreases the base current when emitter-to-collector current is kept constant.