What are Capacitive Load Cells? How do they work?

Capacitive load cells are built on the principal of a change in capacitance when a force is applied on the load cell. Capacitance is the ability of a system to store a charge. If a capacitor is built using the classic parallel plate approach then its ability to store a charge is directly proportional to the area between the two plates and inversely proportional to the gap between the plates.

 

When a force or load or pressure is applied this gap between the plates changes due to the deflection of the housing and results in a disproportionate change in capacitance making capacitive sensors extremely sensitive.

 

The construction of a capacitive sensor is much simpler than constructing a resistive load cell you can read more about it by visiting this page that describes "Why Capacitive Sensors". In addition, by optimizing the starting gaps and/or overlap areas of the two plates, once can vary the sensitivity and output signal to optimize it for various applications.

 

Capacitive techniques can be used to measure gaps (proximity), humidity, tilt, force, torque, acceleration, fluid quality and many other physical parameters! It is a very versatile parameter that offers tremendous sensitivities in a small package.