The circuit shown was found in the February 1994 issue of Electronics Now magazine. The circuit records messages for a few seconds and plays them back as keys are selected.
Using a pair of period A/D converters, this 3-digit circuit was found in the 1992 Radio...
This simple alarm for doors and windows was found in a Japanese publication from the 1960s. The...
This inverter was found in an old European documentation, but components are still current. Only...