> [1809, 1835, 1837, 1840 (Samuel Morse; Morse telegraph) ]

Electric gate > Electric Gate History: https://en.wikipedia.org/wiki/Electric_gate :

> One of the first electric gates was invented by a Canadian Fred W. Watson in 1881. It was designed to be used for railway systems ... “A catch connected with an electro-magnet keeps a gate closed,” reported The National Tribune on October 9, 1884. [3]

Flip-flop (electronics) > History: https://en.wikipedia.org/wiki/Flip-flop_(electronics)