A load cell is a sensor or a sensor that converts a load or force acting on it into an electronic signal. This electronic signal can be a voltage change, a current change, or a frequency change, depending on the type of load cell and circuit used. There are many different load cell types. We offer resistive load cells and capacitive load cells.
The working principle of resistive load cell is piezoresistive. When the sensor applies a load/force/stress, it changes its resistance. When the input voltage is applied, this change in resistance results in a change in the output voltage.
Capacitive load cells work on the principle of capacitance change, which is the ability of the system to retain a certain amount of charge when a voltage is applied. For common parallel plate capacitors, the capacitance is proportional to the amount of overlap of the dielectric between the plate and the plate, and inversely proportional to the gap between the plates.
The force sensor is made by using an elastic member (with a very highly repeatable deflection pattern) to which multiple strain gauges are attached.
In this particular load cell shown on the right, a total of four strain gauges are combined to the upper and lower surfaces of the load cell.
When a load is applied to the body of the resistive load unit as shown above, the elastic member deflects as shown and creates strain at these locations due to the applied stress. As a result, two strain gauges are in a compressive state, while the other two are in a tensile state.
