Hi Joe,
My Interdigitated Electrodes (IDEs) are coated with a polymer and soak tested in saline at 85 C for a long period of time (about 1.5 months). The purpose is to find the lifetime of the polymer. I am using a wheatstone bridge to calculate the unknown resistance of my coated devices by measuring the voltage across the bridge. I have read the resistance with an electrometer (high resistance meter), and also calculated the resistance with the results from a picoammeter. I am expecting a resistance of about a Gigaohm or 10^11, 10^12. So in short, the devices are doing exactly what I want them to do. I am creating this test set up to receive a more accurate measurement. As stated before, when I place the IDEs in the bridge circuit, the voltage repeatedly oscillated from 3 values. I know that this test set up works with a fixed resistor of known value. I am trying to find out why it does not work with the device.
Thank you,
S.L.
