Most weigh scales use a load cell as the sensing element. A load cell is based around a resistor bridge configuration where the resistors are strain gauges. In this example if the user excites a 2 mV per volt sensitivity load cell with 5 volts, customers will have a full scale voltage of 10 mV on the output. The common mode voltage will be 2.5 Volts because the 2 halves of the load cell act as a resistor divider. As the load cell output is directly proportional to the excitation, it is said to be "ratiometric". Therefore, the load cell excitation is used in the system as the voltage reference to convert the load cell output signal, and so a separate voltage reference IC is generally not required. Although this example shows a full scale output voltage of 10 mV, in reality load cells are typically linear for only 60% of their range, so the "real" output range is from 0 to 6 mV.