Capacitive displacement sensor maybe 2

My crude attempt at making a circuit that can detect very minute changes in capacitance by using four capacitors in a wheatstone bridge configuration and a single current limiting resistor. I wanted to use a 5 volt high frequency pulsed DC input similar to what a 555 or microcontroller could output, then amplify the voltage created by the bridge before rectifying to prevent issues with the forward voltage across the diodes if I rectified the output of the bridge directly. The problem I am running into is how long it takes for the output voltage to settle if it's filtered enough, lower capacitance leaves too much of the AC ripple in the signal, so right now I'm trying to find the ideal component ratings to give a smooth but fast changing output. If anyone has any suggestions I would love to hear them, maybe in real time the slow settling won't be much of an issue but I don't have all of the components to test it myself.

published 7 years ago