Load cells are the hidden workhorses behind countless weighing and force-measurement applications.
From industrial scales to aerospace testing rigs, the right load cell helps ensure accuracy, safety, and efficiency. In this post, we’ll explore the most common types of load cells, how they work, and where they are typically used. By the end, you’ll have a solid understanding of why “load cells” are such a fundamental component in measurement systems.
Introduction to load cells
A load cell is a transducer that converts mechanical force into an electrical signal. The quality of this signal and the stability of the measurement depend on the design, material, and construction. There are several families of load cells, each with unique strengths and ideal applications. When selecting a load cell, engineers consider factors such as capacity, sensitivity, temperature tolerance, and mounting configuration.
In this article, we focus on the most common load cells you’re likely to encounter in industry and research. We’ll cover the basic principle of each type, typical applications, advantages, and common cautions. If you’re new to the topic, think of load cells as highly specialized force sensors that translate physical pressure, weight, or tension into precise electrical data.
Foil strain gauge load cells: the workhorse
Foil strain gauge load cells are by far the most widely used type in many sectors. They operate on the principle of strain gauges bonded to a metallic element. When a force is applied, the element deforms slightly, and the strain gauges experience a change in electrical resistance. This change is measured by a Wheatstone bridge circuit and translated into a proportional electrical signal.
- Common configurations: bending beams, shear beams, column, button, pancake, s-beam and in-line threaded load cells
- Advantages: high accuracy, good repeatability, relatively low cost, versatile design and mounting options
- Considerations: temperature sensitivity, creep over time, proper installation to avoid bending stresses from extraneous forces
If you’re assembling a weighing system or looking to accurately measure a force within a specific application, foil strain gauge load cells should be your first choice due to their balance of performance and cost. They are available in a wide range of capacities from a few grams to hundreds of tonnes, making them suitable for everything from kitchen scales to large process weighers.
Bending beam load cells
Bending beam load cells use one or more bending beam elements that deflect under load. The strain gauges are positioned on the top and bottom of the beam such that they experience tension or compression due to the curvature induced under bending.
- Common configurations: single-point, low-profile, and compact multi-point
- Common uses: floor scales, pallet scales, platform scales, and basic industrial weighing
- Advantages: robust construction, straightforward calibration, wide availability
- Considerations: sensitivity to mounting alignment and local bending moments
Bending beam load cells are widely used in mid-range weights and are often found in production lines and warehousing. They strike a balance between size, capacity, and precision.
Shear beam load cells
Shear beam load cells are similar to bending beams, except the guages are positioned on the sides of the strain section to detect shear stress in the sensing element. Shear elements are often suitable for higher loads within the same footprint as an equivalent bending beam load cell. They are known for their ruggedness and lateral stability, which makes them suitable for harsh environments and where space is constrained.
- Common configurations: single-point and double-ended
- Common uses: tank and silo weighing, platform scales in constrained spaces
- Advantages: good durability, relatively simple wiring, high rigidity
- Considerations: calibration can be more complex due to shear geometry
If your process involves heavy loads with limited mounting space, shear beam load cells are worth evaluating for their dependable performance.
Column and button load cells
Column load cells are tall, slender devices designed for vertical force measurement, while button load cells are compact, low-profile sensors used for small-diameter applications.
- Column load cells: often used in tank weighing, crane scales, and large presses
- Button load cells: used for small-scale force measurements, testing machines, and loads in limited spaces
- Advantages: column models offer high capacity and good columnar rigidity; button models deliver high stiffness in a tiny footprint
- Considerations: alignment and installation precision are critical to avoid off-axis errors
These types are crucial in settings where space constraints or high capacities demand a tailored form factor.
S-type and pancake load cells
S-type load cells (also called S-beam) and pancake load cells are common for specific mounting orientations. They differ primarily in shape and mounting compatibility, but both rely on strain gauges to sense force.
- S-type: often used in tension/compression applications, with good versatility for weighing and testing
- Pancake: low-profile, compact, ideal for scale bases and tight spaces
- Advantages: high sensitivity, compact design, straightforward integration
- Considerations: sometimes limited in maximum capacity compared to larger platforms
These shapes are frequently adopted for custom installations where standard platform cells aren’t feasible.
Choosing the right load cell
Selecting the right load cell involves balancing several factors:
- Capacity and overload protection: ensure the unit can handle peak loads with a margin
- Accuracy and repeatability: define tolerance levels suitable for the application
- Environmental conditions: temperature, humidity, chemical exposure, and vibration
- Mounting and installation: consider how the load cell will be integrated into the structure
- Output and electronics: choose compatible signal type (mV/V, mA, or digital)
Final thoughts
Load cells come in a variety of forms, each tailored to different measurement needs. From the ubiquity of bending beam load cells to the rugged resilience of shear beam and the space-saving designs of column and button cells, there is a load cell well-suited to almost any weighing or force-measurement challenge.
When selecting load cells, consider the specific application, environment, and desired signal characteristics to achieve accurate, reliable results. Our engineers are always happy to discuss applications and ensure that the customer ends up with the right load cell for the job.