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i'm doing a project on liquid level sensing and i have chosen to use capacitive liquid level sensing in which i have to change the variation of capacitance in to voltage.so i need a circuit which does this.please help if you know one.
plz plz u'r help means a lot.
Charge the capacitor through a resistor and a switch. Have the switch closed for a fixed period of time. The capacitor voltage at the end of the period will be determined by its capacitance and the time the switch is closed. Buffer this voltage with a high impedance (FET type) op amp follower and read the voltage. After performing the measurement, use a second switch to reset the cap voltage to zero and then do another measurement.