|
BJT |
JFET |
|---|---|
| Unipolar device (current conduction is only due to one type of majority carrier either electron or hole). | Bipolar device (current condition, by both types of carriers, i.e. majority and minority-electrons and hole). |
| The operation depends on the control of a junction depletion width under reverse bias. | The operation depends on the injection of minority carries across a forward biased .junction. |
| Voltage driven device. The current through the two terminals is controlled by a voltage at the third terminal (gate). | Current driven device. The current through the two terminals is controlled by a current at the third terminals (base). |
| Low noise level. | High noise level. |
| High input impedance (due to reverse bias). | Low input impedance (due to forward bias). |
| Gain is characterised by transconductance. | Gain is characterized by voltage gain. |
| Better thermal stability. | Better thermal stability. |
