Table of Contents
What happens to emitter current in collector to base voltage is increased in a BJT?
It is said that because of the Early effect that with an increase in collector to base voltage there is decrease in base width due to which α (the current gain) increases due to lesser recombination of holes and electron, so with increase in α emitter current should decrease according to this equation: IE=ICα.
How the base-emitter current controls the collector emitter current?
The Common Emitter Configuration. One such Common Emitter Amplifier configuration of an NPN transistor is called a Class A Amplifier. A “Class A Amplifier” operation is one where the transistors Base terminal is biased in such a way as to forward bias the Base-emitter junction.
Can base voltage be higher than collector voltage?
If the base voltage is higher than the collector voltage, and the base voltage is higher than the emitter voltage, the transistor is in the “saturation mode” of operation. Current will be flowing into the base (or out of base for PNP).
What factor defines the relationship between collector and emitter current?
The common emitter configuration has a current gain approximately equal to the β value of the transistor itself. However in the common collector configuration, the load resistance is connected in series with the emitter terminal so its current is equal to that of the emitter current.
What is difference between base emitter and collector?
Also note that the collector voltage is higher than the base voltage. The main differences between emitter and collector are doping concentration and size. The emitter is heavily doped, while the collector is lightly doped. You could try to swap them, but you’ll get a very low HFE, probably even less than 1.
Why does collector current increase with base current in BJT?
Why does collector current increase with base current in BJT? The base current in the BJT is due to the recombination of holes and electrons. To neutralize the p region an electron leaves the p region.
What is the effect of biasing on emitter current?
As we know IE=IB+IC here emitter current is input current while collector current is output current (for common base). As we increases input current base current will increases it will allow to increase collector current. So, higher the biasing higher the value of collector current.
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.
How does a BJT circuit work?
Fundamentally the operation of the BJT involves injection of minority carriers from base to emitter (this is the base current) and diffusion of majority carriers (emitter current) from emitter to base. These then drift across the reverse biased collector junction to make up the collector current.