This circuit from the 90s, found in an Electronic Engineering can be used as a shield since its control is digital with TTL logic of 5 V. The components used are still common today.
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...