Capacitive Sensing: Impact of Conductive Liquids/Materials

[leonhart88]

Hi All,

I've been recently reading up on capacitive sensing. Specifically, the case where you have one sensor which is an electrode with a static electric field. When this electrode comes near a conductive target (which is floating and not part of the circuit), the change in potential of the initial electrode can be detected and thus a proximity sensor can be made.

What I am trying to figure out, is if more conductive liquids/materials, result in a larger change of potential and/or capacitance. In other words, will a capacitive sensor work better if the liquid it is trying to detect is more conductive? If so, why?


Thanks.

 

[eljose79]

Hello,

That's a great question! The answer is yes, more conductive liquids/materials will result in a larger change in potential and/or capacitance when using a capacitive sensor. This is because the conductive target will have a greater effect on the electric field created by the electrode, causing a larger change in potential and capacitance.

To understand why this is the case, it's important to understand how capacitive sensing works. A capacitive sensor works by detecting changes in the electric field created by the electrode. When a conductive target comes near the electrode, it disrupts the electric field, causing a change in capacitance. This change in capacitance is then measured and used to determine the proximity of the conductive target.

In more conductive materials, there are more free electrons that can move around and interact with the electric field. This means that the conductive target will have a stronger effect on the electric field, resulting in a larger change in capacitance.

In summary, a capacitive sensor will work better when detecting more conductive liquids/materials because they have a greater impact on the electric field, resulting in a larger change in potential and capacitance. I hope this helps clarify things for you. Let me know if you have any other questions.