Transistors are common and when pressing the switch, only one of the LEDs remains lit. What it will be is not possible to predict, which makes the game possible.
The circuit shown is from an old European publication. In it we have the way to activate a relay...
We found this circuit in a European publication from the 1990s. Transistors are still common types...
This circuit was found in an American documentation and can be added to common amplifiers of any...