Pure water (distilled or deionized) lacks the ions to carry current and will test as very high resistance, 10 MegOhm or above. Most natural, spring or tap water used for drinking or processes have or need those ionic impurities. However, measuring water conductivity is a solid way to measure if an item being rinsed in pure water has been cleaned.
Instructions
1. Measure the distance from the desired testing location to where the DMM can be located. Using the diagonal cutters, cut two pieces of insulated wire, each for the measured distance.
2. Using the diagonal cutters, carefully cut into the insulation about a half inch from the end of one of the wires and twist the wire or cutters to make a circular cut through the insulation without cutting the metal conductor. Use the cutters to pull the cut insulation from the wire. Repeat on the three remaining ends of your two cut lengths of wire.
3. Carefully using the heated soldering iron and solder, press a bared wire end to an electrode and melt solder onto the joint to make an electrical and mechanical connection.
4. Repeat Step 3 with the second cut wire and remaining electrode. You should now have an electrode soldered to one end of each of your cut wires.
5. Use a small amount of epoxy to attach one of the electrodes to the glass (or non-buoyant plastic) disk. Be sure to minimize the epoxy spreading out from under the electrode and do not cover the surface of the electrode with epoxy.
6. Repeat Step 5 with the other soldered electrode, ending with the electrodes a quarter inch apart and the electrodes not touching at any point. Let both epoxied electrodes dry thoroughly before going to the next step.
7. Connect the unattached end of one wire to the positive (+) terminal of the DMM and the unattached end of the second wire to the negative (-) terminal of the DMM.
8. Clean the electrode mounted disk with soap, rinse and then rinse again with isopropyl alcohol before using the electrode disk for the first time. This will limit the contamination introduced by the electrode disk.
9. Switch the DMM to the MegOhm (M and the Omega symbol on the dial) range. Immerse the electrodes in the water being tested.
Tags: diagonal cutters, electrode disk, Repeat Step, Repeat Step with, second wire