A programmable unijunction transistor (PUT) is a three-lead electronic semiconductor device that is similar to a unijunction transistor (UJT), except that its behavior can be controlled using external components. In a UJT, the base region is divided into two parts by the emitter. The two parts of the base form a voltage divider, which sets the operating point of the UJT. That voltage divider can be programmed with two physical resistors connected to the gate terminal of the PUT. This allows the designer some control over the operating point of the PUT.[2][unreliable source?]
Construction
In construction, the programmable transistor is similar to the silicon controlled rectifier (SCR). Like SCR, it consists of four layers ‒ PNPN ‒ but its gate is connected to the second layer (N-type), not the third one (P-type) as with SCR.[1]
Applications
Applications include:
- Triggering thyristors
- Relaxation oscillator
References
- 1 2 Jim Keith. "Programmable Unijunction Transistor Flasher". Archived from the original on 2018-03-05.
- ↑ "PUT - Programmable Unijunction Transistor - Working, Construction, Biasing - D&E notes". www.daenotes.com. 15 December 2017. Archived from the original on 2018-01-05.