This circuit is from American documentation from the 1980s. The transistors are general purpose types and the relay can be 6 or 12 V depending on the supply voltage.
This circuit is intended to trigger an alarm when the input voltage exceeds one value and to...
This circuit, found in a 1986 documentation, uses an optical sensor to count pulses and, in its...
This circuit was found in Delco documentation from 1966. The components are from that time....