This is the receiver for the previous circuit we found in the December 1992 Radio Electronics magazine. The sensor is a photodiode that must have optical features such as lenses.
Found in an Elektor from the 90s, this circuit is based on components that are still common today....
This circuit was found in a Signetics documentation from the 1980s. Next to the figure are the...
This timer of 10, 25, 45 seconds and 5 minutes has its times selected by the keys. The circuit drives...