| 摘要 |
<p>A liquid level and composition sensor includes a first interdigitated capacitor (5) mounted substantially vertically in a tank (1) and a second interdigitated capacitor (7) mounted substantially horizontally in and near the bottom of the tank (1). An electronic processor (9) is reponsive to the value of capacitance of the first capacitor (5) for producing a first voltage signal proportional to the level of the liquid in the tank (1) and is responsive to the value of capacitance of the second capacitor (7) for producing a second voltage signal having a voltage level corresponding to the composition or dielectric constant of the liquid. The processor (9) also multiplies the first and second voltage signals together to produce a liquid level voltage output signal having a constant slope for voltage amplitude versus liquid level, regardless of the composition of the liquid in the tank (1).</p> |
