PURPOSE: To measure the high voltage in an electrostatic charging drum, etc., of an electrostatic copier with simple constitution by forming two pieces of the same series-connected resistors on a piezoelectric ceramic substrate, and comparing the change in resistance value when high potential is applied in the absence of contact to one of them with the resistance value of the other resistor.
CONSTITUTION: The same thin film resistors 2, 3 consisting of nickel, chromium, etc. are formed by vapor deposition on the surface of a piezoelectric substrate 1 of magnesium titanate zirconate niobate type ceramics, etc.. These resistors 2, 3 are connected in series, and electrode plates 8, 9 for application of measuring voltage are disposed via a substrate 1 and an insulation film 7 on the surfaces of one of the resistors, for example, the resistor 3. If the high voltage to be measured is applied to the plates 8, 9 the strain proportional to the applied voltage is generated in the substrate 1, and the resistance value of the resistor 3 is changed by this strain. On the other hand, the resistance value of the resistor 2 does not change. Hence, the applied voltage is known by comparing the resistance values of the resistors 2, 3.
| WO/2001/071367 | MEASUREMENT OF QUANTITIES OF ELECTRIC LINE |
MATSUDA KUNIHIRO
OGATA KAZUO
