Electromechanical Relay-
Who invented it? Joseph Henry did. When was it invented? In 1835. Where was it invented? It was invented at the College of New Jersey. How does it work? Relays control one electrical circuit by opening and closing contacts in another circuit. Why is it important? So that we have light switches and other switches.
The Revolver-
Who invented it? Samuel Colt did. When was it invented? In 1835. Where was it invented? It was invented in Paterson, New Jersey. How does it work? You pull the trigger back and the hammer goes back once the trigger is all the way back the hammer releases hitting the primer propelling the bullet forward. Why is it important? So that we have repeating guns.
Morse Code-
Who invented it? Samuel Morse did. When was it invented? In 1830. Where was it invented? It was between Hamburg and Cuxhaven in Germany. How does it work? It uses dots and dashes to make letters to make words. Why is it important? So that America and the Allies won both world wars.
Circuit Breaker-
Who invented it? Thomas Edison did. When was it invented? In 1879. Where was it invented? It was invented at L Street Station of the Boston Electric Light Company. How does it work? As the moving contacts separate, the circuit inside the circuit breaker opens, interrupting the flow of current and protecting the system from further damage. Why is it important? So that we have batteries