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.
In the figure we have a Texas Instruments circuit for TTL interfacing using discrete transistors. The two...
This circuit was found in Radio Electronics magazine from June 1963. The range is small and the...
The project presented in a 2009 documentation is intended for radio amateurs operating in the...