AW: [sdiy] Zener-oscillators

[René Schmitz]

Hi Harry and all,

> The four layer (npnp) device family does what you are trying to do by
> design, rather than by accident (like transistor avalanche).  These
> would include the four layer diode (now very rare) and  (with a gate
> added), the SCR, Unijunction and Programmable Unijunction Transistor,
> and maybe the Diac (though I'm not sure of that one).

The Unijunction is not a four layer device. As its name says it has one
junction. I remember vaguely that the emitter is also heavily doped in
these, so it could indeed be the same avalanche effect that exists in
the transistor.


Cheers,
  René

-- 
uzs159 at uni-bonn.de
http://www.uni-bonn.de/~uzs159