Circuit diagram of Darlington configuration

In electronics, the Darlington transistor is a semiconductor device which combines two bipolar transistors in tandem (often called a "Darlington pair") in a single device. This gives it high current gain (commonly written β), and takes up less space than using two discrete transistors in the same configuration. The total gain of the Darlington is the product of the gain of the individual transistors. A typical modern device has a current gain of 1000 or more. It has more phase shift at high frequencies than a single transistor, and hence can become unstable with negative feedback much more easily. The base-emitter voltage is also higher; it is the sum of both base-emitter voltages and for silicon-transistor >1.2 V.

This configuration (originally realized as two separate transistors) was invented by Bell Laboratories engineer Sidney Darlington. The idea of putting two or three transistors on a single chip was patented by him, but not the idea of putting an arbitrary number of transistors, which would cover all modern ICs.

External link

• Darlington’s Contributions to Transistor Circuit Design