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Electrolytic tilt sensors must be operated in the AC mode. Any DC will cause the level to become unstable and even inoperable. The amount of current through the level must not exceed the maximum. Currents that are above the typical recommended value will cause the level to self heat and the readings will drift. The impedance value of the level must be specified to match the type of circuit used in order to limit the current.

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Figure 2: Structure of Electrolytic Tilt Sensor

Excitation

The electrolytic tilt sensor(level) can be energized in a number of ways depending on the applications and performance required. Typically, there are two ways to energize and read the level.

One way to energize the level is the use of a bridge type circuit as shown in figure 3.  This configuration allows for the adjustment of the bridge resistors to match the internal impedance of the level. It must be noted that the electrolyte's impedance will change with temperature. The impedance is inversely proportional to temperature. This can cause readings to change with temperature when the level is in  an unbalanced position. Therefore, temperature compensation is required in an uncontrolled environment.

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Figure 3: AC Bridge Circuit

References

1. Wong,T.D., Evaluation of Electrolytic Tilt Sensor for Wind tunnel Model Angle-of-Attack (AOA) Measurements, Langley Research Center, NASA, USA

2. The Fredericks Company(2008). Retrieved from http://www.frederickscom.com/sens_tech_select.tpl
3.