This General Electric circuit, in a documentation from the 1960s, allows the use of high resistance resistive sensors with unijunction transistors in a relaxation oscillator.
This filter was found in the October 1969 issue of Radio Electronics magazine. The frequency...
The circuit in the figure has the same purpose as the previous one (CBV15991E), except that it has a...
Found in a Popular Electronics from the 90s, this circuit can be adapted to use LEDs. The power...