Zinc-oxide varistor
Varistor de óxido de cinc
- Date
- 1968-1971 · confidence high
- Place
- Kadoma, Osaka, Japan
- Credited to
- Michio Matsuoka (Matsushita Electric)
- Field
- Matter & energy
What it is
A zinc-oxide ceramic with additives whose resistance drops sharply above a certain voltage, acting as a surge valve. It protects everything from sockets and electronics to high-voltage lines.
Silicon-carbide varistors (such as GE's 'Thyrite') had been used since the 1930s; Matsuoka's novelty is zinc oxide, patented in 1968 and published in 1971.
What it led to
- metal-oxide surge arresters in substations
- household surge protectors
- replacement of silicon-carbide varistors