How can the triode be judged to form a composite tube?
In other words, the collector current direction of the input tube is the same as that of the base current of the output tube and forms a channel, which can form a composite tube (Darlington tube). Its relationship is: Ic1=Ib2; beta = beta 1 * beta 2The polarity (PNP or NPN) of the composite tube is determined by the polarity of the input tube
There are four kinds of two triode compound, see the following figure, as long as there are two transistors, it may form a composite tube.
The collector current of the signal input tube (usually small power), whether it flows out of the collector or emitter, flows through the base of the output tube (flowing in or out) and can form a composite tube (Darlington tube).
