I working on my senior design project, and I need a way to measure very small levels of capacitance (as well as change in capacitance). The capacitor will be on the order of picofarads (at the moment the capacitor I am going to make will vary between 15-25 picofarads), and I haven't been able to find a method to accurately measure levels this small.
I did run across a variation of a Wheatstone bridge that uses capacitors:
where the change in capacitance can be described by:
However, the book is not clear on what Cv(0) is (in the numerator). Is that the value when the variable capacitor is the same as the other capacitors in the bridge?
Does anyone else know of any other method for measuring capacitors on the picofarad level with sub-picofarad resolution?
I did run across a variation of a Wheatstone bridge that uses capacitors:
where the change in capacitance can be described by:
However, the book is not clear on what Cv(0) is (in the numerator). Is that the value when the variable capacitor is the same as the other capacitors in the bridge?
Does anyone else know of any other method for measuring capacitors on the picofarad level with sub-picofarad resolution?