Found in an EDN from the 1980s, this circuit uses a double 555. The circuit activates a relay that controls a horn or siren. Next to the diagram we have the timings.
This circuit is from a 1980s Motorola documentation. The circuit can be made with modern...
This configuration, already presented in other points of this section and website, is of a...
This hydromassage circuit was found in a 1967 General Electric publication. The SCR is according to the...