This circuit was found in a Philips documentation from 1967. The circuit uses components from the time that have current equivalents such as BC548 for transistors.
The basis of this circuit is the 723, an old integrated circuit not easier to find these days. The...
This circuit was obtained from a 1967 General Electric manual. The circuit uses components of the time,...
The thermistor used in this circuit must have a resistance at room temperature between 10 and...