Low Resistance Adapter
Constructing the Special Test Clips.The 4-wire measurement system requires that two different leads make contact with each terminal of an unknown resistance. If we could make an alligator clip in which the two jaws are insulated from one another and each jaw is connected to a separate lead we would have it. There is probably a better way and I may figure one out in time but for now all I can come up with is an ordinary wooden clothespin.
Talk your wife out of two clothespins. Look through her supply and pick out two of the best looking and identical pins. Cut out four pieces of unetched copperclad pcboard as shown. Place two of the pieces copper to copper and place them between the jaws of a clothespin. If they don't sit flat file away some of the wood of the pin so it fits together. Now apply some Elmer's Contact Cement to the pcboard material and place them between the jaws of the clothespin. Be careful not to get any glue between the two copper sides of the material. Do this for both pins and let it dry for about five hours.
These clips are a little clunky but they work fine on wire leads. On military style transformers the terminals are too close together to get the clothespins on. That's why I need to come up with something else.
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This site begun March 14, 2001
This page last updated August 18, 2001