A vacuum-tube computer, now termed a first-generation computer, is a computer that uses vacuum tubes for logic circuitry. Although superseded by second-generation transistorized computers, vacuum-tube computers continued to be built into the 1960s. These computers were mostly one-of-a-kind designs.
The use of cross-coupled vacuum-tube amplifiers to produce a train of pulses was described by Eccles and Jordan in 1918. This circuit became the basis of the flip-flop, a circuit with two states that became the fundamental element of electronic binary digital computers.
