This circuit was found in the February 1970 issue of Radio Electronics magazine. The integrated circuit is a type of the time. It consists of a high-gain differential amplifier.
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...