Signals of up to a few tens of kilohertz can be generated by this circuit found in a European publication from the 1980s. Transistors admit equivalents and the unijunction can be 2N2646.
This battery-powered micropower supply was shown in Radio Electronics magazine in 1991. The...
Found in a 1965 Electronic Design, this circuit can be made with modern equivalent transistors. The...
In this circuit, the current in solenoid X1 can be adjusted and its intensity measured to the...