Resources
Common LVDT Technical Topics
Below are technical topics commonly discussed with our LVDT customers.
Cable and Connector Assemblies
The Series 310-320 and 350 Gaging LVDTs both terminate in an MS style connector. Mating connectors and assemblies are sold separately. In instances where a connector or cable assembly is required, part numbers can be found in this TekNote.
Calculation Methods for Ideal Straight Line Non-Linearity Comparison
Each transducer is calibrated and supplied with a calibration report describing important product details such as non-linearity. Non-linearity is calculated by comparing actual data against ideal data. Calculation methods for the ideal data include Best Fit Straight Line, Best Fit Straight Line Through Zero, and Zero Based Average Terminal.
Many of our LVDTs are supplied with a core tapped at both ends. To attach the core to a moving object, an extension rod made of a non-magnetic, poor electrically conducting material must be used. Tables of Extension Rods made by Trans-Tek are shown in the spec sheets for each individual transducer Series. This TekNote explains the best way to make you own.
It is possible to use LVDTs in a vacuum environment, but certain factors such as outgassing and heat dissipation need to be addressed.
Passive Signal Conditioning for DC LVDTs
In the Series 200 and 240, the LVDTs are powered by a DC voltage, and provide a DC voltage output. The normal output is bi-polar, ranging from a negative voltage to positive voltage passing through zero, or the null position. In certain applications, it is necessary to have a unipolar output or bipolar output of a certain magnitude. Using a simple resistive voltage divider network, the output can be offset and scaled.
Synchronous vs. Asynchronous Demodulation
AC LVDTs require a signal conditioner – referred to as an Oscillator/Demodulator – to create DC-in/DC-out operation. This TekNote reviews two popular methods of demodulation, and why Trans-Tek uses asynchronous demodulation in their Series 1000 O/Ds.