explain the enhancement and depletion mode of jfet along with their transfer curves
Answers
In field effect transistors the depletion mode and enhancement mode are two major transistor types corresponding to whether the transistor is on or off at the zero gate - source voltage.
1.) Enhancement mode
It is most common in switching element.
The device is off at zero gate voltage.
Pulling an enhancement mode gate voltage towards its drain voltage turns it on.
2.) Depletion mode
The device is on at zero gate source voltage.
Junction field transistors are depletion mode since the gate junction would forward bias if the gate were taken more than a little from source towards drain voltage.
The depletion layer of the channel is very small and the JFET acts like a voltage controlled resistor.
Cut-off Region – This is also known as the pinch-off region were the Gate voltage, VGS is sufficient to cause the JFET to act as an open circuit as the channel resistance is at maximum.