Load cells are the type of transducers that transform force into an electric signal and are used in variety of industrial monitoring applications of weight and force ranging from transportation, oil and gas, industrial automation, and aerospace. There are different types of load cells and the most common type is strain gauge based load cell. Other includes low capacity, mid-range, and high capacity load cells. Low capacity load cells are idyllically used in wind tunnel testing, medical testing equipment, part-counting scales, and weigh check. These low capacity load cells have the range starting from 25 grams up to 150 pounds. Different types of low capacity load cells includes single point, S-beam, bending beam, and isometric beam. All these types of low capacity load cells are available in digital instrumentation or analogue including, digitizers, amplifiers or signal conditioners, indicators, and displays. Load cells can be divided into four classes based on the direction of loading that includes tension, alternating, compression, and bending.
Low capacity load cells are used in several laboratories to detect the small addition of weight like of small grains, or small force. There are different designs or circuits available to measure the tension forces, or compression. Similarly, Wheatstone bridge is used to detect the changes in the resistance and then convert the force into voltage. This report will discuss the primary application of load cells that is weight measurement.
Low range beam type load cells or transducers are attached with the specific region of the elastic beam that is shaped in form of an “I” shape. This load cell has calibration in V/mV/Ω., high input resistance, and low profile design. The strain gauge occurs when the weight is exerted to the beam. At this point, the resistance changes and that triggers the bridge to convert the force into voltage as according to the proportion of weight. This experiment can easily be conducted in the lab in less than 2 hours.
Budget
Low Capacity Load Cell (Beam Type) - $100/cell
Price of eight low capacity load cells - $800
This experiment will provide good understanding of the functions of low capacity load cells to the students. This basic experiment will help students in first understanding the concept and the carrying on with the larger experiments. Even this experiment can be expanded with usage of more number of load cells to make the system more sensitive and making the concepts further cleared. The basic components that are used in this experiment are resistances, power source, external force, and tools to measure output voltage .
New equipment can be connected with this project to make it easier for the students to read the voltage changes with resistances and applied force. FUTEK has recently introduced the first Miniature Digital Load Cell along with USB output. This technology is not only useful at the graduate level in universities and colleges, but may also be used in different market segments like pharmaceuticals, nanotechnology, medical device manufacturers, aeronautical experiments, and many more. Giving an understanding of bigger projects to the students of mechanical engineering at this level will help those achieving greater levels. They would be able to invent even better technologies in future .
Works Cited
Futek. A Powerful Combination. 2014. http://www.futek.com/newsletter/March09.htm.
UTM. "Experiment 2: Strain Gauge." n.d.
