A load cell is a force sensing module - a carefully designed metal structure, with small elements called strain gauges mounted in precise locations on the structure. Load cells are designed to measure a specific force, and ignore other forces being applied. The electrical signal output by the load cell is very small and requires specialized amplification. Fortunately, Phidget Bridge Interfaces will perform all the amplification and measurement of the electrical output, see the Connection & Compatibility tab for details.
Load cells are designed to measure force in one direction. They will often measure force in other directions, but the sensor sensitivity will be different, since parts of the load cell operating under compression are now in tension, and vice versa.
This Single Point Load Cell is used in small jewelry scales and kitchen scales. It’s mounted by bolting down the end of the load cell where the wires are attached, and applying force on the other end in the direction of the arrow. Where the force is applied is not critical, as this load cell measures a shearing effect on the beam, not the bending of the beam. If you mount a small platform on the load cell, as would be done in a small scale, this load cell provides accurate readings regardless of the position of the load on the platform.
Load cells require a power source and produce a very small voltage differential when under strain. In order to read this signal, an amplifier or a board with a high-precision analog-to-digital converter is required. For more details and a list of Phidgets that will connect to this load cell, see the Connection & Compatibility tab.
|Make sure to calibrate your load cell before using it. You can find information on how to calibrate the cell in the Load Cell Primer. You should also have a look at the User Guide for the bridge interface board that you're using to read the load cells.|
Load cells and strain gauges produce a very tiny voltage differential and must be read by a high-resolution analog-to-digital converter. You can connect this load cell to a bridge interface as described in this table:
|Controlled By||Bridge Input|
|Sensor Type||Shear Load Cell|
|Weight Capacity Max||780 g|
|Maximum Overload||936 g|
|Zero Balance||± 11.7 g|
|Cell Repeatability Error Max||± 390 mg|
|Cell Non-Linearity Max||390 mg|
|Cell Hysteresis Max||390 mg|
|Temperature Effect on Span||39 mg/°C|
|Temperature Effect on Zero||39 mg/°C|
|Rated Output||800 μV/V|
|Rated Output Error Max||± 100 μV/V|
|Output Impedance||1 kΩ|
|Supply Voltage Max||5 V DC|
|Compensated Temperature Min||-10 °C|
|Compensated Temperature Max||40 °C|
|Operating Temperature Min||-20 °C|
|Operating Temperature Max||55 °C|
|Cable Length||200 mm|
|Cable Gauge||30 AWG|
|Material||Aluminium Alloy (LY12CZ)|
|Screw Thread Size||M3x0.5|
The Data Sheet below has a comprehensive glossary that describes in practical terms the meaning and usefulness of the specifications.
|Image||Part Number||Price||Sensor Type||Weight Capacity Max||Creep||Zero Balance||Cell Repeatability Error Max||Cell Non-Linearity Max||Cell Hysteresis Max|
|3132_0||$6.00||Shear Load Cell||780 g||1.6 g/hr||± 11.7 g||± 390 mg||390 mg||390 mg|
|3133_0||$7.00||Shear Load Cell||5 kg||5 g/hr||± 75 g||± 2.5 g||2.5 g||2.5 g|
|3134_0||$7.00||Shear Load Cell||20 kg||20 g/hr||± 300 g||± 10 g||10 g||10 g|
|3135_0||$7.00||Shear Load Cell||50 kg||50 g/hr||± 750 g||± 25 g||25 g||25 g|
|3136_0||$45.00||Compression Load Cell||50 kg||20 g/hr||± 500 g||± 100 g||100 g||—|
|3137_0||$45.00||Compression Load Cell||200 kg||* 40 g/hr||* ± 2 kg||* ± 200 g||* 400 g||—|
|3138_0||$45.00||Compression/Tension Load Cell||100 kg||—||—||—||—||—|
|3139_0||$7.00||Shear Load Cell||100 g||—||—||± 50 mg||50 mg||50 mg|
|3140_0||$50.00||Compression/Tension Load Cell||500 kg||—||—||—||—||—|
|3141_0||$50.00||Compression Load Cell||1 Mg||—||—||—||—||—|