We all are familiar with digital weighing machines or weight scales at hospitals, gyms, malls, or even at homes. Upon weighed on them, the measured mass of the body will be displayed digitally. Have you ever thought of working principle of this process? Continue reading for a better understanding.
It is nothing but an energy conversion is employed for the display of our weight in kilograms. This energy conversion is made possible by an electronic device called load cell. In the circuitry of weighing machine, load cell is inserted along with other elements.
What is a load cell?
Load cell is one type of transducer. We all know that transducer is an electronic device that can convert one form of energy to another. Likewise, upon given pressure or a physical force, load cell just converts the force (pressure) to its corresponding electrical signal.
Load cell are classified based on their working principles. The basic working mediums are given below.
- Strain gauge
- Hydraulic
- Capacitive
- Pneumatic
Out of the above four, commonly used is the strain gauge type. And also, it is that type of load cell which is inserted in a digital weight scale for the display of body mass.
How the body weight is displayed digitally?
The maincomponents of a digital weight machine circuitry are strain gauge transducer, current (voltage) measuring part, and the display unit.
The strain gauge transducer has a Wheatstone bridge configuration of strain gauges powered by a battery source. We know that the Wheastone bridge is used for the measurement of unknown resistance. The same principle is applied here. So when a body is kept on the weight machine, a corresponding variation in resistance happens in the bridge circuit. This variation generates a linear electrical signal. The magnitude of this electrical signal is proportional to the exerted force (weight of the exerted object). And thus, the body weight is displayed digitally on the screen.
