Field Effect Transistor
The Junction Field Effect Transistor
|Bipolar Transistor||Field Effect Transistor|
|Emitter - (E)||Source - (S)|
|Base - (B)||Gate - (G)|
|Collector - (C)||Drain - (D)|
Bias arrangement for an N-channel JFET and corresponding circuit symbols.
Output characteristic voltage-current curves of a typical junction FET.
- Ohmic Region - The depletion layer of the channel is very small and the JFET acts like a variable resistor.
- Cut-off Region - The gate voltage is sufficient to cause the JFET to act as an open circuit as the channel resistance is at maximum.
- Saturation or Active Region - The JFET becomes a good conductor and is controlled by the gate-source voltage, (Vgs) while the drain-source voltage, (Vds) has little or no effect.
- Breakdown Region - The voltage between the drain and source, (Vds) is high enough to causes the JFET's resistive channel to break down and pass current.