The structure of a junction field effect transistor seems to be very
similar to that of unijunction transistor. Schematically, the main
difference seems to be that the JFET is run wit back bias and modulates
the impedance of the semiconductor channel while the UJT is also back
biased but finally becomes forward biased as the as the emitter junction
voltage increases. Typically, that is achieved by charging a capacitor
connected to the emitter. The result is a regenerative build-up of
carriers which quickly discharge the capacitor.
Are there any reasonably priced JFETs that can work as UJTs? What part
numbers are there? Are there any precaution to use to prevent damage to
the device?
- posted
9 years ago