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.
Found in old documentation, this circuit uses components that are still common on the market. The...
This circuit activates a relay by activating one of a series of optical sensors that can be...
We found this circuit in a 1996 publication. Equivalent components can be tried, especially in the...