Parametron

The parametron is a logic circuit element invented by Eiichi Goto in 1954.^[1][2] The parametron is essentially a resonant circuit with a nonlinear reactive element which oscillates at half the driving frequency.^[2][3] The oscillation can be made to represent a binary digit by the choice between two stationary phases π radians (180 degrees) apart.^[2][4]

Parametrons were used in early Japanese computers from 1954 through the early 1960s. A prototype parametron-based computer, the PC-1, was built at the University of Tokyo in 1958 and later recognized as part of the IEEE Milestone for the parametron.^[5] Parametrons were used in early Japanese computers due to being reliable and inexpensive but were ultimately surpassed by transistors due to differences in speed.^[6]