| 摘要 |
<p>PURPOSE:To perform temperature compensation and to realize a range finder with less errors by connecting a pulse generator between two electrodes of a capacitor having three-layer structure through resistors, and detecting the phase difference between both electrodes. CONSTITUTION:A detecting electrode 20 and a compensating electrode 22 are provided on both sides of a planar dielectric body 26 of a capacitor C. The electrode 20 is connected to one terminal of a DFF 16 through an inverter 10 and also connected to a pulse generator 14 through a resistor R1. Meanwhile, the electrode 22 is also connected to the generator 14 through a resistor R2 by the same way. When a material to be detected comes close to the capacitor, the stray capacitance of the detecting electrode 20 is increased, and symmetry of the capacitor C is collapsed. The phase of the electrode 20 is delayed from the phase of the electrode 22. Therefore, the phase relationship between the inputs for the DFF 16 is reversed. A distance can be measured with a voltage at a time point when the output state is reversed. Since the generator 14 is symmetrically connected with the equal resistors, temperature compensation can be performed readily.</p> |
