This lead-acid battery charger was found in a Popular Electronics from the 90s. The circuit has a maximum current of 2 A, being suitable for powering inverters in emergency lighting systems.
The operational amplifier used on this 1968 circuit is not common today. However, the setting can be...
This circuit was found in an old American magazine and could make use of more modern components...
This two competitor version of the game is shown below and uses lamps as indicators. You can...