1. Definition of the “Load Cell”

As explained in the Introduction to Load Cell 1, load cells are sensors that convert force (mass, torque) into electrical signals and output the electrical signals. Load cells are also called “load transducers.”

In the dictionary, a load cell is described as a “weight measurement device necessary for electronic scales that display weights in digits.”

Load cells can be classified according to the following operational principles:

1. Load cells that utilize liquid pressure or air pressure
2. Load cells that utilize elasticity
3. Load cells that utilize a magnetostriction effect or piezoelectricity effect

Among the many kinds of load cells, the strain gauge load cell is the most prevalent.

Therefore, when we say “load cell,” we are generally referring to strain gauge load cells.

While there are many measurement devices other than strain gauge load cells, such as magnetostrictive sensors, capacitance sensors, and gyro sensors, this article will focus on a description of strain gauge load cells. 

2. Characteristics of the Strain Gauge Load Cell 

The characteristics of the strain gauge load cell are as follows:

1. Highly precise measurements with little influence due to temperature changes
2. Long distance communication or command is possible as the output is an electrical signal. Easy to do calculations and processing with a computer.
3. Small size given its capacity compared with other types of load cells.
4. The deflection due to the deformation of the spring material is small, and the spring material’s natural frequency is high. Thus, it is possible to shorten the measurement time. Also, measurement of dynamic phenomena is possible.
5. Maintenance is easy and it has a long operating life because there are no moving parts or any parts that generate friction.
6. Production is easy because of the sensor’s simple operation principle and small number of components.
7. Excellent fatigue characteristics as long as the device is not overloaded, and its performance can be maintained semipermanently.
8. The strain gauge load cell was once very difficult to manage because it had a miniscule electrical output of μV. However, this problem has been solved thanks to advances in electronic technologies. 

* Spring material and strain gauge