| 摘要 |
PURPOSE:To measure accurately electrostatic capacity by using an oscillation frequency which is a function of the electrostatic capacity to be measured. CONSTITUTION:Electrostatic capacity 1 (cx) and the known electrostatic capacity 2 (cr) can be connected alternately to the same oscillator 3 by a changeover switch 4 so that they are elements of the oscillator 3. The changeover switch 4 is controlled by an operating circuit 5 so that it is closed to the side of the known electrostatic capacity 2 or the side of the electrostatic capacity 1 to be measured, and an oscillation frequency fx at the time when the switch 4 is closed to the side of the electrostatic capacity cx to be measured is detected, and the operation based on an oscillation frequency fr at the time when the switch 4 is closed to the side of the known electrostatic capacity cr is performed in the circuit 5 to obtain the electrostatic capacity to be measured in accordance with a prescribed formula, and the result is outputted to a means 6. Thus, the accurate electrostatic capacity is measured. |
