| 摘要 |
PURPOSE:To eliminate a movable part and to prevent electrolytic corrosion, by detecting the difference between the dielectric constants of air and a liquid as the difference in electrostatic capacity between detecting electrodes. CONSTITUTION:D flip-flop 10 functions as a monostable multivibrator by returning a Q output thereof to a clear terminal CL through resistances R2 and R1 and by always holding a D input at a high level. The detection electrodes 11 and a DC cut capacitor C2 are connected in series between connection point of a resistances R1 and R2 and the earth. The electrodes 11 are fixed with an insulator 12 by leaving a prescribed interval and are arranged by a suitable means for hanging with a string (as shown in the figure) at the liquid level position to be detected. When the liquid level is low and the electrode 11 is in air, the output pulse width is small and is extended with the rise of the liquid level. |
