Using transistors at the time, this circuit was found in a 1970s documentation. Transistors support modern equivalents for 2A currents at least in the case of the output transistors.
This circuit, found in a 1986 documentation, uses an optical sensor to count pulses and, in its...
This different alarm system, found in an old publication, uses the starter chain to protect the...
This circuit was obtained from an American publication of the 80's. The integrated circuit is of the...