What is base width in transistor?
What is base width in transistor?
BASE WIDTH MODULATION OR EARLY EFFECT IN TRANSISTOR In Active region emitter base junction is forward biased and collector base junction is reverse biased. So the depletion layer width at emitter base junction is negligible as compared to depletion layer width at collector base junction.
What is base in bipolar junction transistor?
The base region of a BJT is the region, which has opposite polarity charge carriers from the emitter and the collector regions. So that the base region of a BJT transistor is very thin and is lightly doped with current carriers.
What are the consequences of base width modulation?
We can at- tribute three consequences to base-width modulation; (1) the narrower base width means that there is less chance for recombination, causing αF to increase as |VCE| increases; (2) the concentration gradient of minority carriers within the base increase (as diffusion current is proportional to the …
What is the importance of early effect in BJT?
Early Effect: A large collector base reverse bias is the reason behind the early effect manifested by BJTs. As reverse biasing of the collector to base junction increases, the depletion region penetrates more into the base, as the base is lightly doped.
Why is base made thin?
Solution : 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.
What is Q point in transistor?
The operating point of a device, also known as a bias point, quiescent point or Q-point, is the steady-state DC voltage or current at a specified terminal of an active device such as a transistor with no input signal applied.
Why width of base region is made very thin?
Why BJT is called a current controlled device?
A BJT is a current controlled device because its output characteristics are determined by the input current. A FET is voltage controlled device because its output characteristics are determined by the Field which depends on Voltage applied.
What is leakage current in transistor?
The current in the blocking direction in a diode is called the leakage current. There are no leakage currents in the transistor with its two diodes if one electrode is open at a time. The amounts of these leakage currents depend only a little upon the value of the voltage applied (saturation).
Why BJT is called current controlled device?
What is thermal runaway in BJT?
Thermal runaway The problem with increasing temperature causing increasing collector current is that more current increase the power dissipated by the transistor which, in turn, increases its temperature. This self-reinforcing cycle is known as thermal run away, which may destroy the transistor.
