Anodized Treatment Micro Load Cells CZL639HD Scales Sensors To
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, the 1046
PhidgetBridge will perform all the amplification and measurement of
the electrical output.
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.
|1. Rated Load||100-750 (g)|
|2. Rated Output||0.8mV/V|
|3. Zero Balance||±1%F.S|
|4. Input Resistance||1050±50Ω|
|5. Output Resistance||1050±50Ω|
|6. Excitation Voltage||9-12VDC|
|11.Operating Temperature||-20ºC To +65ºC|
|12.Temperature Effect on Zero||0.05%F.S/10ºC|
|13.Temperature Effect on Span||0.05%F.S/10ºC|
|15. Safe Overload||150%F.S|
|17. Cable||200mm(flat 4-wires)|
NumberType="1" TCSC="0" w:st="on">5mm 4-wire shielding cable)
How they work
Strain-gauge load cells convert the load acting on them into
electrical signals. The measuring is done with very small resistor
patterns called strain gauges - effectively small, flexible circuit
boards. The gauges are bonded onto a beam or structural member that
deforms when weight is applied, in turn deforming the strain-gauge.
As the strain gauge is deformed, it’s electrical resistance changes
in proportion to the load.
The changes to the circuit caused by force is much smaller than the
changes caused by variation in temperature. Higher quality load
cells cancel out the effects of temperature using two techniques.
By matching the expansion rate of the strain gauge to the expansion
rate of the metal it’s mounted on, undue strain on the gauges can
be avoided as the load cell warms up and cools down. The most
important method of temperature compensation involves using
multiple strain gauges, which all respond to the change in
temperature with the same change in resistance. Some load cell
designs use gauges which are never subjected to any force, but only
serve to counterbalance the temperature effects on the gauges that
measuring force. Most designs use 4 strain gauges, some in
compression, some under tension, which maximizes the sensitivity of
the load cell, and automatically cancels the effect of temperature.
Other types of load cell exist which have half bridges (2 strain
gauges) or quarter bridges but they require additional hardware to
operate since you must complete the bridge to get the most accurate
What is a Wheatstone bridge?
A Wheatstone bridge is an electrical circuit used to measure and
unknown resistance by balancing 2 legs of a bridge circuit. One leg
of which contains the unknown value. Wheatstone bridges are made up
of 4 resistors or loads in a square with a voltage meter bridging 2
corners of the square and power/ground connected to the other
corners. In the case of a load cell, these resistors are strain