This circuit can be adjusted between 0.2 and 2 V to trigger with chosen voltages comparing them with the input voltages. We found it in a 1967 documentation.
This circuit was published in a 1977 Radio Shack catalog. The PNP transistor may be BD135 and NPN...
May 2017 - ROHM is announcing the availability through Mouser Electronics of a broad line of fast...
This temperature compensated circuit was found in a Popular Electronics of the 1990s. The circuit...