|You can make your own conductivity tester from a few inexpensive parts or order an assembled version from Flynn Scientific. If you order a pre-assembled one, you will probably want to add a battery clip so the battery can be easily connected.. All parts are available from Radio Shack .|
1 - LED (Light Emitting Diode)
|Completed Tester (battery not shown)|
|If you've purchased the assembled tester
all that's necessary is to add the battery clip and battery.
There are 4 wire ends that are not connected. 1 red and 1
black are held together by a small piece of clear "spaghetti"
tubing. These 2 wires are the tester's "probe" that you will
insert into the substance to see how/if it conducts.
Make sure these bare ends are kept separate and do not touch each
Connect the remaining two ends to the wires on the battery clip (red to red and black to black). Snap the battery clip onto the battery and touch the "probe" wires together. The led should light. I have purchased battery clips with the wires connected wrong. If the LED doesn't light, disconnect the battery clip wires from the tester wires and re-connect in reverse (red to black and black to red). Once the tester is working, use a small piece of electrical (scotch tape or even adhesive tape will also work) to insulate the bare wires where the battery clip is connected to the tester.
Disconnect the battery clip from the battery when the tester is
not in use to prevent accidental discharge of the
|If you wish you can make your
own from the parts listed above. Start by removing about 1/2
inch of the insulation from each end of the 3 wires. Assemble
the components as shown in the diagram to the left. The
wires may be connected by twisting them together tightly and
wrapping the bare portion with tape. For added reliability you
may wish to solder the connections. Be careful as the plastic
LED body will melt if too much heat is applied.