- 2022-03-25 The ZNR High Energy Varistors(HF series) with a guaranteed 150 °C has been commercialized.
- 2020-12-01 The part number of D type E-S1 series has been added (ø11 series).
- 2020-06-01 Some parts of Varistor Unit has been discontinued (ERZA1P/2P/3P/4P).
- 2019-12-02 Some parts of Varistor Unit has been discontinued (ERZA1E/2E/3E/4E).
- 2019-08-01 Simulation data has been posted.
- 2019-02-22 The V type E-S1series with a guaranteed 125 °C has been commercialized.
- 2019-01-16 "Surge Absorbers" page has been updated.
- 2016-10-28 Registration certificates of quality and environment certifications (ISO, TS) are available for download
- 2016-07-24 "Cross reference" has been posted
What is ZNR surge absorber?
"ZNR" stands for Zinc-Oxide Non-liner Resistor, the product name of a voltage-dependent resistor (registered trademark) developed by Panasonic (formerly Matsushita Electric Industrial) in 1968. This product is generally called a zinc oxide (ZnO) varistor or metal oxide varistor (MOV).
The ZNR has a voltage-current characteristics curve horizontally symmetrical with respect to the Y-axis with the curve rising as sharply as the curve of a Zener diode. With such characteristics, the ZNR absorbs harmful surge voltage instantaneously to protect electronic equipment from it. As a surge protection component, the ZNR is incorporated in office automation apparatuses, communication equipment, household appliances, and automobiles, etc., and is used for various applications, such as to protect transmission cables, in a wide range of fields.
Surge voltage absorption principle and its effects
Applying a surge voltage results in a surge current flow through a ZNR surge absorber,
which clamps down the surge voltage.
The ZNR has non-linear voltage-current characteristics. When a voltage higher than the varistor voltage of the ZNR is applied to the ZNR, a current flowing through the ZNR increases exponentially.
The ZNR exerts these characteristics when an abnormal voltage, such as a surge voltage, is applied thereto, allowing current to flow through the ZNR, thereby absorbing the surge voltage.