Darlington Transistor Working:

Darlington Transistors Working – A Darlington-connected transistor pair is shown in Fig. 11.6. The current gain of the power transistor can be considerably improved if the base drive current is obtained from another transistor. This is called a Darlington arrangement. The driver transistor can be incorporated on the same silicon chip, with overall current gains of 250 being possible, but with a longer switching time.

Darlington Transistor Working

Circuits using power transistors or a Darlington Transistors are expected to become smaller in size and less costly compared to circuits using thyristors. Individual devices are now available having a voltage rating of 1200 V and a continuous-current rating of 300 A. With a reduced voltage rating of 100 V, a continuous-current rating of 750 A is possible.