Relays were first built in 1835, and were patented & ready for mass production in 1840. You can build electromechanical computers out of them: https://m.youtub

Relays were first built in 1835, and were patented & ready for mass production in 1840. You can build electromechanical computers out of them: https://m.youtube.com/@ClicketyClack https://m.youtube.com/@ClicketyClack