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Darlington Pair » Electronics » Basic Circuits » Darlington Pair » Let's go... » Experiment 5 - Darlington Pair IV

Experiment 5 - Currents in a Darlington Pair

Consider the circuit shown in which the currents are indicated....

Into the base of the transistors T1 flows the current IB1 = 0.1 μA. Assuming a gain βT1 = 200 results in an emitter current IC1 = 20 μA

The collector current of transistors T1 now flows into the base of transistors T2. Since the collector current is the sum of the emitter and base current, flows IB2 = 20,1 μA into the base of transistor T2.

With a gain βT2 = 200 the emitter current is IC2 = 4,02 mA...

Circuit diagram currents in the Darlington pair.

...which is the result you measured approximately in the last experiment.