Expert: Marc Ebelini - 8/16/2010

Question
I've read a previous question that you answered sometime ago about blind encoders which relates to this. I was wondering if you could tell me the principle of operation of transducers in solid-state type blind encoders. I am already familiar with optical encoders in encoding altimeters and aneroid-type blind encoders.

Answer
Followup: Has promised I followed up on solid state Ic's. To answer your question further I found that instead of frequency they now use several methods. Both using resistance. One is a piezoresitive pressure sensor the other uses a bourdon tube that is used to change the resistance. In both cases since resistance is so temperature sensitive the temperature monitoring must be included with the IC. Because of great advances in high resolution resistance to digital circuits now makes that possible. Have an inexpensive digital scale that uses one of those piezo resistive devices which is extremely accurate. It goes to one tenth of a gram.
The data sheets did not give me any detail as to what the circuit include, only box diagrams.