Page 2 - Transistor and FET New

Current amplification in CC configuration is defined as The ratio of change in emitter

current ( Δ IE) to the change in base current ( Δ IB)

6. What is Junction Field Effect Transistor(FET)?
Junction Field Effect Transistor (JFET) A junction field effect transistor is a three
terminal semiconductor device in which current conduction is by one type of
carrier i.e., electrons or holes.
In a JFET, the current conduction is either by electrons or holes ( Unipolar) .
The JFET has high input impedance and low noise level.
7. Schematic Symbol of JFET

8. Difference between Transistor nd FET
Sl.no Transistor FET
1 a bipolar transistor. unipolar transistor.
2 the input circuit of an ordinary input of a JFET is reverse
transistor is forward biased biased
3 base current might be a few μA IG = 0A
9. What is Pinch off Voltage (VP)?
Ans: It is the minimum drain-source voltage(VGS) at which the drain current
essentially becomes constant.

PInch off Voltage

10. Advantages of FET?

Sl.no Advantages of FET
1 It has a very high input impedance
2 JFET has a negative temperature co-efficient of resistance.
This avoids the risk of thermal runaway.
3 A JFET has a smaller size, longer life and high efficiency.

4 A JFET has a negative temperature co-efficient of resistance. This
avoids the risk of thermal runaway.

Dr P I Mandi, Dept. of Electronics , Basaveshwar Science College,Bagalkot # 2019 -20