This circuit was found in the May 1959 Radio Electronics magazine. Its purpose is to provide bias voltages for circuits under test. The circuit is isolated from the power grid.
This simple circuit controls the brightness of an LED from LDRs, NTCs, PTCs or other resistive sensors....
We found this circuit in a 1990 documentation. It draws one out of 10 numbers and during the draw...
The circuit shown in figure 3 uses a programmable unijunction transistor (PUT) of the BRY39 type...