This circuit appeared in Radio Elecronics magazine in 1968. The operating circuit is a general-purpose type at the time and the power supply must be symmetrical.
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...