LVDT Signal Conditioning Circuit

[SarahT]

Hi there,

I've been working on a signal conditioning circuit for a Linear variable differential transformer (LVDT) and I've created a circuit to help simulate it. To design it I have used Proteus software as at the time it's was only software available to me that has all the components i required, however my knowledge of it isn't the best.

When i run the circuit I get no errors but there is no output on the oscilloscope. I don't know if I have connected it wrong or i'm missing something in the circuit.

There is an image of the circuit attached.

Any help will be appreciated.

Thank you,

Sarah

 

[duke37]

The circuit is too complicated for me. 17 voltage regulators seems to be 15 too many.
I thought that the LVDT circuits used an AC drive and a synchronous detector.
Could you describe what it is intended to do?

Is the output of U3 shorted to earth?

 

[SarahT]

Yes it is a complicated circuit but I don't know any other way of doing it.

The op-amps that are in place act as a synchronous demodulator. Yes, it should be AC supplys where i have put the voltages. A very stupid mistake on my part.

U3 isn't shorted to earth or atleast it shouldn't be. Why is that?

Thank you for your reply,

Sarah

 

[duke37]

U3 output is shorted to earth, pin 3 has a staight wire finishing in a connection to earth. I have no idea why this is!

Please give a description of the theory behind the circuit.

 

[(*steve*)]

Also, you are using positive voltage regulators for your -ve rail.

It might be useful for you to tell us what your power supply is, and what voltage rails are required for your ICs.

Typically you might have a single +ve regulator and a single -ve regulator and each IC is powered from the same rails.

Your lack of experience in this area doesn't inspire me with confidence about the rest of your circuit (which I have not looked at).