Unijunction transistor--is interchanging of B! and B2 oK and why.

[Salmon Egg]

I am returning to the old days trying to use a unijunction transistor for a
simple relaxation oscillator. B2 appears to be usually connected to the
case.

Considering how a UJT is constructed, it should make little difference which
polarities are used across B2-B2 except for what should be minor detail. Is
that so? Is power dissipation or shielding affected by having B2 connected
to the case?

Again, the UJT and JFET seem to be of similar construction except for
possibly the heft of the main N channel. Can a JFET work like a UJT?

Bill
-- Fermez le Bush

 

[Michael Black]

I am returning to the old days trying to use a unijunction transistor for a
simple relaxation oscillator. B2 appears to be usually connected to the
case.

Considering how a UJT is constructed, it should make little difference which
polarities are used across B2-B2 except for what should be minor detail. Is
that so? Is power dissipation or shielding affected by having B2 connected
to the case?

Again, the UJT and JFET seem to be of similar construction except for
possibly the heft of the main N channel. Can a JFET work like a UJT?

I can't remember enough about UJTs to be able to tell you about
the first.

But no, UJTs and JFETs are not the same thing. Just because
the schematic symbol is similar looking does nto make them
the same.

On the other hand, you can "synthesize" a UJT with a pair of
transistors connected properly. It was in the magazines in the old
days, and I'm sure there's information somewhere on the internet about
doing this.

Michael