How Digital Scales Work

How Digital Scales Work

Joelle Alcaidinho
Mar 31, 2010

It is no surprise that we at Unplggd prefer digital scales. We've rounded up our picks for kitchen scales, shown you a neat bathroom scale hack, posted about a scale that looks like a book and now it's time to talk about the tech behind these scales.

With some help from HowStuffWorks and eHow.com we were able to understand the basics of how digital scales work.

Instead of the springs that mechanical scales use, digital scales work through the use of a strain gauge load cell that converts the force of a weight to an electrical signal. When an item is placed on the scale, the weight causes the load cell to bends downwards, deforming the strain gauge.

The strain gauge then takes this deformation and converts it to an electrical signal. Because the load cell has an electric charge, as it moves downwards, the electrical resistance changes. The resulting small change in resistance becomes an electrical signal. After the signal is run through an analog to digital converter, it then passes through a microchip that turns the data into the numbers that are then indicated on the LCD display as the weight of the object.

(Bathroom Scale Images: Flickr user Micah Dowty under license from Creative Commons.)

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