EXCLUSIVE FORUM FOR MACHINE DISMANTLERS AND REPAIR PEOPLE > Hammond
> Heavy Machinery
> Components
> ( qty 4 ) ujt osc, sawtooth/ ± pulse generator, flasher
( qty 4 ) ujt osc, sawtooth/ ± pulse generator, flasher
a.k.a. Uni-Junction Transistor (UJT)
* Only 3 Leads in a TO-92 Package
Please, don't let the name "transistor" confuse you. This is a rare, unique, even oddball but fun device for any experimenter who takes the time to explore it's properties. They don't make these any longer and our stock is limited.
Actually, the UJT doesn't work anything like a conventional bipolar transistor. It doesn't even have the same junction configuration. The UJT has two bases with an emitter in between. And it has no collector. The UJT is actually a Negative-Resistance device that can be used as an oscillator, much like a Tunnel Diode.
The UJT enjoyed popularity after it's introduction in the late '50s, particularly for firing SCRs. But with the introduction of DIP8 timer chips, the UJT has all but disappeared from sight. Nevertheless, the sheer simpicity, even compared to the LM555 or LM3909, makes them perfect for exploration by curious experimenters.
These UJTs were manufactured by General Electric numbered "GE 5L507". A Google search will yield volumes of information on UJTs and their applications. Enjoy!
* Sawtooth, + Pulse, - Pulse
* Very Linear Ramp ( R2 > 10K )
* Simpler than LM3909, LM555
* Simpler than any other Flasher
* Increased CT = brighter flash
