Load Cell is a force load transducer which converts force into a measurable electrical output. Although there are many varieties of load cells, strain gage based load cells are the most commonly used type. The majority of modern weighing systems rely on strain gauge load cells for the conversion of weight or load change into usable electrical output. Load cells are used in several types of measuring instruments such as universal testing machines.

Load Cell Operating Principle

The force load measurement is indirect and happens in two stages. Through a mechanical arrangement, the force being sensed deforms a strain gauge. The strain gauge measures the deformation (strain) as an electrical signal, because the strain changes the effective electrical resistance of the wire. A load cell usually consists of four strain gauges in a Wheatstone bridge configuration. Load cells of one strain gauge (quarter bridge) or two strain gauges (half bridge) are also available. The electrical signal output is typically in the order of a few millivolts and requires amplification by an instrumentation amplifier before it can be used. The output of the transducer is plugged into an algorithm to calculate the force applied to the transducer.

Every load cell is subject to “ringing” when subjected to abrupt load changes. This stems from the spring-like behavior of load cells, exhibiting vibrations at its natural frequency. An oscillating data pattern can be the result of ringing. Ringing can be suppressed in a limited fashion by passive means. Alternatively, a control system can use an actuator to actively damp out the ringing of a load cell.

Load Cell Types

  • Load Cell types based on working principle:

    • Cantilever Bending Beam Load Cells
    • Compression Load Cells
    • Tensile Load Cells
    • Universal Load Cells
    • Shear Load Cells
    • Torque Load Cells
    • Hollow Load Cells
  • Load Cell types based on construction:
    • Bending Beam Load Cells
    • Parallel Beam or Binocular Beam Load Cells
    • Canister Load Cells
    • Shear Beam Load Cells
    • Single Column Load Cells
    • Multi-Column Load Cells
    • Pancake Load Cells
    • Load Button Load Cells
    • Single Ended Shear Beam Load Cells
    • Double Ended Shear Beam Load Cells
    • S-Type Load Cells
    • Inline Rod End Load Cells
    • Digital ElectroMotive Force Load Cells
    • Diaphragm Membrane Load Cells
    • Torsion Ring Load Cells
    • Bending Ring Load Cells
    • Proving Ring Load Cells
    • Load-Force Pin Load Cells
    • Axial Torsion Load Cells
    • Load-Force Washer Load Cells
    • Low Capacity Load Cells
    • Low Profile Interface Load Cells
    • Single-Point Load Cells
    • Multi-Axis Load Cells
    • Calibration Grade Load Cells
  • Load Cell types based on electrical properties:
    • Resistive Load Cells
    • Piezoelectric Load Cells
    • Capacitance Load Cells
    • Analog Load Cells
    • Digital Load Cells
    • Wireless Load Cells

Applications of Load Cells

Load Cells are used in Force measurement, Portable weigh scales, Platform scales, Electronic weighbridge or truck weighing, Electronic crane scales, Hopper/Tank/Silo weighing, Finding Center of gravity, Onboard weighing, Railcar weighing, Structural health monitoring, In-motion dynamic weighing check weigher, Batch weighing, Monitor inventory, Feedback control, Impact measurement, Force gauge, etc.