GE Unijunction Transistors From the Early 1960s


The Unijunction Transistor was developed at General Electric in the 1950s, and became a widely used semiconductor device. It was a three terminal device with one emitter and two base contacts, using originally a silicon grown 'bar' with two diffused base regions.

Before the development of the first timer IC it was used in a range of timing circuits. It was also used in sensing circuits, phase control and SCR trigger applications. It was the latter which benefitted GE the most. GE produced the first Silicon Controlled Rectifiers in the late 50s which drove their pre-eminence in power electronics.


 

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