In 1954, Japanese engineer Eiichi Goto invented the parametron — a resonant circuit using a ferrite core and capacitor that oscillates between two phase states (0° and 180°) to represent binary digits, requiring no tubes, relays, or transistors. Three-input parametrons naturally act as majority gates, and by fixing one input or reversing coupling transformer polarity, AND, OR, and NOT logic can be derived. Several Japanese computers were built on this technology, including the PC-1 (operating at 15 kHz, adding fixed-point numbers in 270 microseconds), the PC-2/FACOM 202 (100 kHz, 9,600 parametrons), and the FACOM 212. Parametrons also interfaced with core memory in a non-destructive read mode. Speed limitations (clock frequencies in the 140 kHz range) ultimately caused parametrons to be overtaken by transistor-based designs, but they represent a notable chapter in computing history, particularly in Japan.
Questions this post answers
What is a parametron and how does it represent binary data?
A parametron is a resonant circuit — typically an inductor or capacitor whose reactance is varied at twice its resonant frequency — that oscillates at half the pump frequency. Two equally stable oscillation states exist, separated by 180° of phase, which represent binary 0 and 1. Three weakly coupled parametrons form a natural majority gate; fixing one input yields AND or OR, and reversing a coupling transformer gives inversion. Engineers exploring unconventional logic implementations find the full parametron circuit details worth tracking on daily.dev.
What were the clock speed and performance specs of the PC-1 parametron computer?
The PC-1 operated at 15 kHz and could add fixed-point numbers in 270 microseconds, using 4,200 parametrons and consuming 3 kW of power. Its successor, the PC-2 (commercialized as the FACOM 202), ran at 100 kHz with 9,600 parametrons but drew 10 kW. The theoretical maximum for a high-speed parametron was around 6 MHz, but practical computer clock frequencies topped out near 140 kHz. Retrocomputing milestones like these surface regularly for hardware history readers on daily.dev.