This circuit was obtained in a 1967 Raytheon manual. The company's component is an optical coupler with a photo-resistor and a lamp. Transistors support equivalents.
This circuit is from American documentation from the 1980s. The transistors are general purpose...
This circuit was found in a Popular Electronics of the 1990s. The sensor is a rotating mechanical...
The purpose of this circuit is to sense the water level in the windshield wiper reservoir. The circuit...