Experiment 9 - The Sziklai Pair

In a Sziklai pair you combine an NPN with a PNP transistor. This circuit is also often referred to as a complementary Darlington pair.

Build the circuit shown. By turning the Potentiometer P1 you realize that the circuit behaves like a ordinary NPN Darlington Pair.

Circuit of Sziklai pair. (Enlarge) Also the gain of the Sziklai pair βS is approximately βS =  βT1 ×  βT2. (See Experiment 17 to derive this formula.) However, the Sziklai pair has another advantage that makes it interesting for applications...

Circuit diagram of a Sziklai pair.