In fact, this circuit from the 60's applies to photographic printers of the time, timing the lighting of a 20 W lamp. The components are from the period.
This circuit was found in a 1998 documentation and its purpose is to automate controls by timing its...
This circuit is from a 1977 Radio Shack documentation. It produces a modulated sound of good...
This second-order filter was found in old American documentation and can be applied to other...