Ratiometric

Ratiometric is used to describe an output signal which changes in proportion to a change in input or supply voltage.

A typical ratiometric device would be a strain gauge output pressure sensor, where the output sensitivity is described as a ratio between output and input supply voltage.

If the sensor is described as having a 3 mV/V ratiometric output sensitivity, this means that the full span output will increase by 3 millivolts for every 1 volt increase in supply voltage.

If for example the supply voltage for a sensor with 0.5...4.5 V output at 5 V supply increases by 10 % to 5.5 V, the output signal also increases by 10 % to 0.55...4.95 V. In contrast, sensors with an internal reference voltage have a non-ratiometric output signal.