This circuit is from the manual of the integrated circuit used. Similar versions appear on this website and even in this section.
Found in Ferranti's 1968 documentation, this circuit uses a Darlington photo transistor to drive a...
Found in documentation from the 70s, this circuit uses components from that time. Some of these...
This circuit monitors the state of a 12 V battery and can be used directly with one, or even in a...