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SOC Corporation was established in Tokyo on November 27, 1958, as San-O Industrial Corporation. San-O means “Three Kings” in Japanese, and derives from SOC’s founding spirit of placing the utmost value on its customers, shareholders and employees.

At the time of SOC’s founding, fuse-elements were made of either alloys or pure metals. Alloys used included lead (Pb) and tin (Sn); pure metals included zinc (Zn), copper (Cu), and silver (Ag). Whatever they were made of, however, there was only ever one element per fuse.

Televisions in 1962 were in the midst of the transition from black and white to color sets. At that time, color televisions often had spare fuses attached to the rear of the set since their fuses tended to blow with great frequency.

The engineers of the time understood that television fuses frequently blew because of the large transitional current which flowed for several milliseconds when televisions were switched on and which charged the capacitor circuit. This current could reach a maximum surge waveform of 60 A, which could not be handled by the single straight-wire element fuses of the time. SOC invented a wound fuse-element which would not blow for surge currents, but would for currents which could be potentially dangerous. Starting with the color television, this invention ushered in an age for all electronic equipment wherein spare fuses were no longer necessary.

When appliances which require a large starting torque for their motor circuits (such as refrigerators, air conditioners and washing machines) are switched on, a trapezoidal-shaped waveform with a large current flows through them. Up until 1975, the fuses which were used to deal with these large currents employed elements made of metals with low melting points, and took advantage of the mechanical function of springs. As a result, the fusing performances of these fuses varied widely. By winding the element around a ceramic core, SOC invented a new type of element, and with this invention began manufacturing time-delay fuses with extremely stable fusing performances.

Following the establishment of its first overseas subsidiary in New York, USA, in April 1975, SOC opened the Tochigi Factory in Nasu, Tochigi Prefecture, Japan, in December 1978.

Photo : SOC Tochigi Factory

In the late 1970’s, the telephone entered the age of the electronic automatic exchange (EAX). As EAXs are computer-controlled, demand rose for quick-acting fuses to prevent damage from lightning strikes. Accepting a request from AT&T, SOC met this demand in 1980 with the development of the KS21505 (the SM Series) quick-acting fuse, which with an operation time of 10 μs was the world’s fastest quick-acting fuse.

Taking the first letters of the words in its original company name, San-O Industrial Corporation renamed itself SOC Corporation in April 1983. In that same year, SOC contributed to the miniaturization of circuits for the coming age of handheld electronics through the development of microfuses with leads.

SOC established sales offices in the Netherlands and Singapore in 1990, and began production at its newly opened factory in Akita Prefecture, Japan.

Photo : SOC Akita Factory

In 1987, SOC began production of the world’s first surface mount type fuses (the MCF Series). In 1994 SOC developed a sub-miniature glass tube fuse (the SHV Series) with a rated voltage of 400 V and a size of 20 mm in length and 5 mm in diameter. And in 2001, SOC succeeded in the development of an astonishingly small fuse (the 28CDA) capable of breaking a short-circuit current of AC 600 V / 60 A, which is the assumed fault contact for primary power lines as stipulated in Telcordia GR-1089-CORE Second-Level AC Power Fault, an American telecommunications equipment standard.

In 2002, SOC succeeded in eliminating lead from its products in order to comply with the EU RoHS Directive. In 2006, SOC developed a fuse (the DC500VBC1028) which was capable of breaking a current of DC 500 V / 100 A despite its relatively small size of 28 mm in length and 10 mm in diameter.

SOC is currently answering requests from the automobile industry for the development of fuses to protect their next generation circuits.

SOC is committed to delivering fuses with the world’s greatest capabilities and highest quality.

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