Found in a 1968 Mullard manual, this circuit measures temperature by infrared radiation. The sensor is of the type that is difficult to obtain today.
This circuit maintains on a flashing LED at a frequency determined by the capacitor. The...
After starting, this circuit turns off the relay in a time that depends on the 4020 pulse-count. This...
This sophisticated circuit is from a 1975 documentation. The components are from the time and the...