We found this circuit in a magazine 73 for radio amateurs from the 80's. The circuit makes use of an epochal component which is programmed according to the table beside the diagram.
This circuit is from the 80's integrated circuit manual itself. The component is not as common today...
This circuit has been found in an old documentation and therefore uses a lamp as an indicator. In a...
This circuit generates a tone of a bell and can be used in this type of application. The circuit is...