LVDT (Linear Variable Differential Transformer)

LVDT (Linear Variable Differential Transformer) is one type of displacement sensor. LVDT sensor works on the principle of magnetic flux generated by induction in the iron core from the primary coil. LVDT input voltage is alternating voltage (AC), so that the output voltage produced is also in the form of alternating voltage. When the input voltage LVDT in the form of alternating voltage is not constant magnitude, then the output voltage that occurs will not be fixed. This means that the LVDT excitation voltage is changed, the sensitivity of the LVDT also changed. In addition, because the output voltage is alternating voltage, so the motion direction hard to be estimated. LVDT movement direction can be known based on the phase between input and output voltage. In addition, LVDT using alternating voltage of this kind are only suitable for devices that work-based alternating voltage, so that the tools based on DC voltage will be difficult to utilize this type of LVDT.


In this final study design and manufacture of LVDT signal ICs based on AD598. Design process was conducted on the design of the power supply and signal conditioner design using IC AD598. The procedure of signal conditioner design based on the design procedure set forth in IC AD598 datasheet. Electronic circuit design results is made in the form of PCB. In the PCB design process, used software Protel 99 SE. After the power supply and signal conditioner is made, then performed the calibration process which includes static and dynamic calibration to determine the linearity and sensitivity of the LVDT system.

Results of static calibration and dynamic calibration showed that the signal conditioner is able to work well until the frequency of 15 Hz with linearity greater than 0.99.