The basic weighing technology used in these scales is predominantly the electrical strain gauge.  The strain gauge offers a less expensive and more rugged physical package than the somewhat upscale magnetic force restoration load cell, and while somewhat less accurate, it still provides adequate accuracy and resolution for most industrial applications.  There are still straight mechanical platform scales offered but these are a small minority and slowly vanishing.

The strain gauge load cell, then, is the heart of the modern platform scale.  Most of the strain gauges used are of the simples cantilever types and rely on four resistive elements that are bonded to the strain gauge surfaces in such a way that when weight is added to the platform two of the resistive elements are stressed (shortened by pushing) and two are strained (lengthened by pulling).  The four elements are arranged in a Wheatstone Bridge electrical circuit that provides an output signal proportional to the weight.

Anatomically the platform section can be likened to a sandwich.  The upper piece of bread is the platform plus any weights put on it.  The meat of the sandwich is the second layer, and that is the strain gauge.  The bottom layer is the frame of the scale which rests on the weighing surface (usually the floor) and has leveling feet for making the weight vector perpendicular to the weighing surface.  Thus, in order for any weight to be transferred from the platform to the frame it must go thru the load cell on the optimum weighing axis.

Now, the next critical piece of the anatomy is called the display, but it is usually far more than just a display.  In order to amplify the error signal, scale it properly for calibration, correct for non-linearity’s, correct for temperature changes, accommodate the tare function, change from analog signal to digital value, a modern digital computer with memory is required.  Which means that the software required to accomplish these functions must be provided by the manufacturer.  The programmer has largely replaced the adjuster as the man who adds value to the product.  Some platform scales have a feature where the scales resolution may be momentarily increased to that of a laboratory scale which can be useful when grater sensitivity is required.