| 摘要 |
PURPOSE: To provide a varistor which has a good pulse absorbability with low varistor voltage by forming an oxide layer on the surface of a semiconductor layer composed chiefly of strontium titanate, and by specifying a resistance value of the semiconductor layer which is put between two electrodes which are formed on the oxide film. CONSTITUTION: This ceramic varistor is made by forming an oxide layer 2 on the surface of a semiconductor layer 1 composed chiefly of strontium titanate, and then forming a first and a second electrode 3, 4 on the oxide film 2. The voltage between the first and the second electrode should be 9V or below when a current of 10mA flows between the first and the second electrode. Also, a resistance value of the semiconductor layer 1 between the first and the second electrode should be 1/3000 or below that of the entire body between the first and the second electrode when a current of 10mA flows between the first and the second electrode 3, 4. The resistance value of the semiconductor layer 1 between the first and the second electrode is adjusted by changing the setting of a reducing atmosphere at the time of burning or oxidation process related conditions. |
