This tuned circuit was found in a 1966 Electronic Circuit Handbook. The transistor can be any modern general-purpose equivalent.
The figure shows the basic configurations for unijunction oscillators. They are relaxation...
We found this circuit in a 1985 documentation. The 4-LED bargraph is excited by an input voltage. The...
I found this circuit in a Popular Electronics from 1992. The circuit can be easily implemented with BC549...