Working with an "old school" circuit, looking for some rules of thumb! I'm also trying to avoid having to write out the whole transfer function because those rusty joints have seized up long ago. It really takes me a long way back just to think about it.
This technology has mostly gone away in favor of better technique, equipment and sensors. But a few examples are still in use. And searching for such a thing is difficult because quality control has borrowed the term for an unrelated usage.
Basically, the circuit consists of a square wave generator (less than 50% duty cycle) that drives a small transformer at about 320Hz. On the primary side, the voltage steps from about 0.6 VDC to Vcc. On the magnetically isolated side, the secondary is about 3.8 times the magnitude and evenly split about the zero cross over while unloaded.
The secondary feeds a variable Z coil (iron core-moves with the machine) sensor and the resultant is a DC signal that drives a VSD. Then it feeds into a full wave bridge with capacitors in parallel with the bottom two diodes. This yields a positive DC pulse (that looks a lot like the primary side) and the negative pulse is active (made positive by the Full Wave Bridge) it illustrates what happens when there is no more power available for the core of the transformer and critical damping where the capacitors dump back their little bit of stored energy.
I'm really trying to get to how this works without having to derive the transfer function. Does this sound like anything you have worked on?
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A great troubleshooting tip...."When you eliminate the impossible, whatever remains, however improbable, must be the truth." Sir Arthur Conan Doyle
Tuning Up a Variable Q Circuit
Re: Tuning Up a Variable Q Circuit
