Selection of Valves (Vacuum Tubes)

The first vacuum tube, in its simplest form, was invented by John Ambrose Fleming in 1904. When the First Generation of computing emerged in the 1940s, they used a combination of valves (vacuum tubes) and relays as electronic switches. A valve is an electronic switch that controls the flow of electrical current. Valves are a basic electronic component used for circuitry and memory in First Generation computers.