Mechanical Scale. Any of several mechanical devices that measure the weight of an object. The two most common types are spring scales and balances. A balance measures the weight of an object by comparing it to standardized weights. In compares the weight of the object placed in a pan on one end of the balance with standard weights placed in a pan on the other end. A spring weighing scale measures the forces necessary to stretch or compress a spring and convert this displacement to weight on an analog indicator.
Things to Consider: SPRING: Capacity, Resolution, Zero-adjust, Dial locking assembly to hold reading, Rugged construction if required by application (e.g. 18-gauge steel subframe), Housing material, Fatigue-resistant spring, Dimensions, Warranty BALANCE: Capacity, Resolution, Weighing units, Beam calibrations, Pan/plate dimensions, Housing dimensions, Tare function, Magnetic damping, Shipping weight, Warranty.
Weight Transmitter. An electronic device that processes the low voltage electrical output from mechanically deforming load cells, amplifies that signal, and uses it to operate an integrated digital or analog readout, or to control another device. A load cell is a transducer which converts force into a measurable electrical output. Although there are many varieties of load cells, strain gauge based load cells are the most commonly used type. They offer accuracies from .03% to .25%full scale, and are suitable for most industrial applications.
Things to Consider: Dimensions (Grid and Carrier), Nominal resistance (ohms), Resistance tolerance per package, Max permitted bridge energizing voltage (Vrms), Foil measuring grid (material and thickness), Carrier material, Substrate thickness, Cover thickness, Connection dimensions, Gauge factor, Gauge factor tolerance per package, Reference temperature for thermal properties, Service temperature for measurements (static or dynamic), Temperaure characteristics of materials, Temperature compensated range, Tolerance of temperature compensation, Maximum strain, Hysteresis, Fatigue, Smallest bending radius, Transverse sensitivity, Warranty.