This circuit was found in a 1980s documentation. The circuit uses common components having an output of 10 Hz per centigrade degree of variation. The sensor is a transistor.
This source for devices for automotive use was found in a 1985 documentation. The power...
We found this circuit in an old Popular Electronics. It is possible to light a common neon lamp...
This circuit has an opposite action to the previous one, triggering when light falls on the...