Load cells can be categorized by their output signal or their method for detecting weight. In all cases, load cells are methods for measuring mechanical force and turning the measurements into digital values to be read and recorded.

• Hydraulic Load Cells measure weight based on the change in pressure placed on an internal fluid. With a diaphragm hydraulic force sensor, the load acts on a loading head that causes a piston to compress fluid in a confined elastomeric diaphragm chamber. As the force increases, pressure on the fluid rises. The output is linear and unaffected by the amount of fluid or the fluid’s temperature.
• Pneumatic Load Cells operate on a force balance principle and use multiple dampener chambers that provide highly accurate readings. They have an elastic diaphragm that is attached to a platform surface. When an object is placed on the load cell, pressurized air or gas balances its weight. The air needed to balance the weight determines the weight of the object. Pneumatic load cells are used in industries where small weights are measured and cleanliness and safety are important. They are explosion proof, unaffected by changes in temperature, and do not have any fluids that would contaminate a process if the diaphragm of the load cell ruptured.
• Strain Gauge Load Cells are the most common type of load cell with a capacity rating between 500g to more than 500 Ton. They have high-resolution digital indicators with ideal force transfer standards. Strain gauge load cells are transducers that change electrical resistance when under stress or strain with the resistance proportional to the strain placed on the cell. The readings from a strain gauge load cell are linear and can be converted to force and weight.
• Canister Load Cells are compact and cost effective load cells used for single and multiple weighing applications. As with many load cells, canister load cells are hermetically sealed and water resistant. Their heavy duty design is able to withstand harsh inhospitable environments. Canister load cells are ideal for axial compression applications and can measure a variety of capacities such as tanks, hoppers, and vehicles. Compression Load Cells have a strain gauge to measure pushing force along a single axis, which is denoted as a negative force. They are perfect for applications with limited space and have excellent long-term stability.
• Tension Load Cells have a strain gauge to measure pulling apart or positive force along a single axis.
• Force Sensors use strain gauges to test push-pull and measure flow. They are similar to “load cells” but measure loads in all directions. Earth’s gravitational force is not relevant to how they are installed.
• Pressure Sensors are transducers that are similar to load cells that measure pressure, applied force, and strain in gas pressure, altitude, and liquid pressure. Their sensors are often piezoelectric.
• Piezoelectric Crystal Force Transducers are used for measuring crystalline materials. When a force is applied to a crystalline material, an electrical charge is generated. A piezoelectric force transducer, with its charge amplifier, measures the electrical charge and converts the measurement into a digital signal.
• Miniature Load Cells are compression load cells designed to work with high capacity loads where there is minimal space. They can be miniature or subminiature with a diameter of 51 mm or two inches. Their small size and diameter make them ideal for test benches, industrial weighing, and prototypes. Miniature load cells have twist lock connectors and cable connections with metric configurations ranging from 0 to 100 N to 0 to 50,000 N.
• Donut Load Cells also known as thru-hole load cells, measure compressive forces and are called donut load cells because of their shape. They are smooth and round with a hole in the middle for parts or bolts and are used in oil and gas pumps. Shear Beam Load Cells have a straight block of material fixed on one end with loaded material on the other. Beam load cells, known as bending load cells, are used for industrial weighing, including industrial floor scales and tank, silo, and onboard vehicle weighing. Bending beam load cells are low capacity load cells made of aluminum alloys with a capacity of 1 to 500 kg.
• Capacitive Load Cells use capacitance, the ability to store a charge, as a measuring method. They have two flat parallel plates. When current is applied to the plates, it is stored between the plates. The amount of charge that is stored, capacitance, determines how large the distance is between the plates. When a load is placed on the plates, the distance between the plates shrinks, which can be calculated into weight. There are two types of capacitive load cells, which are low and mid.
• Low Capacity Transducers are miniature transducers used in medical testing equipment, wind tunnel sensors, and weight counting machines. They are limited to measuring weights between 25 grams and 100 kg, making them suitable for residential and retail machines.
• Mid Capacity Transducers can accurately measure weights between 200 to 20,000 kg and are ideal for industrial and manufacturing applications. Common uses are industrial scales, truck and truck weighing, bolt force measurement machines, and platform scales.
• Micro Load Cells are resistive load cells that use the principle of zero piezoresistivity. When a load, force, or stress is applied to the sensor, the resistance changes, which causes the output voltage to change because the input voltage has changed. Multi-Axis Load Cells are designed and manufactured to measure a multitude of forces simultaneously using a single load cell. They provide multiple bridges that precisely measure force from one direction with little or no cross-talk from other forces or moments.
• High Capacity Load Cells can measure extreme loads such as the roof on a mine and the thrust force of a rocket. They are integrated into machines, systems, and instruments and are small, lightweight, and compact. High capacity load cells are custom designed to fit the requirements of each individual application and may need to be inserted into an existing mechanism.
• Specialty Transducers are used underwater or in outer space. They can measure compression, tension, pressure, capacity, and much more.
• Pin Load Cell is made with load measuring pins, or load pins, that sense applied force using strain gauges installed in a small bore that runs through the center of the load cell. They are used on anchors, shackles, sheaves, bearing blocks, and pivots. They work well underwater because the pin is protected, and the load cell is made of cable and stainless steel with hermetically sealed end caps.
• Pancake Load Cells can be used for both tension and compression measurements in materials and component fatigue testing as well as axial force measurements, where a high accuracy, low-profile device is needed. They have female threads through their center and several holes around the outer ring for mounting purposes. Pancake load cells can measure from 50 lbs up to one million lbs.
• Dynamometer Load Cells or dynos, measure force, torque, and power. A dyno, combined with load cell sensing technology, creates a dyno load cell, which is used to measure engine power output. They are rather expensive and only used when absolutely necessary.
• Single Point Load Cells have only one operating load cell and are used in individual device applications, such as supermarket scales.
• S Beam Load Cells are bending beam load cells used for weighing applications under 22 kg. They have a metal spring element that deforms when a force or weight is placed on the load cell. The strain gauge in the load measures the fractional change in the length of the deformation. S beam load cells are used in scales and tension applications.S beam load cells are very popular due to their precision, low price, and ease of installation. They are designed for inline applications and are sensitive to outside loads and torque. S beam load cells must be centered to the load and have proper directionality.
• Multi axis load cells are capable of measuring tension, compression, and torque in all directions. They have multiple strain gauge bridges to measure forces and torque in one direction with little to no interference from forces applied in other directions. Multi axis load cells save space in assembly and installation time.

The OIML requires specific information placed on certified load cells to identify their capacity, accuracy class, application, temperature, and humidity rating.

• Accuracy Class – A, B, C, or D
• Number of divisions – Placed after the accuracy class in thousands
• Applications – Compression, tension, beam, or universal indicated by an arrow
• Temperature Rating – Given if the default range does not apply
• Humidity Rating – SH for steady state humidity or NH for no humidity

Load cells can be classified using the following criteria.

• Direction of Loading :

When classified by the direction of load detection, load cells can be divided into the following types: tension, compression, alternating, and bending.

• Precision :

Based on precision, load cells can be classified as ultra precision, precision, standard, and general-purpose.

• Air tightness Hermetic (Hermetic Seal) Type:

This type encloses the areas of the strain gauges within a case and shields them from the outside air.

Open Type: With an open type, soft resin or rubber is used as the temperatureproof material.

Explosion-Proof Type: Due to its structure, this type can be certified as flame proof

Load cells are often classified by their outer shape. Classifications include the Can type, the S type, the washer type, and the beam type.