The 3M model 703 static electric field measurement gun can measure the magnitude and polarity of a static field. They use a 200 millicurie tritium source and a high resistance circuit to do the measurement. The tritium source is used as an ionization source. It runs off of two 9V batteries and looks like a Buck Rogers ray gun.
You calibrate the thing by unrolling a section of tape from a roll of adhesive tape. Adhesive tape is made sticky by exposing it to what amounts to a Tesla coil during the manufacturing process. We used to make electrets by charging a disk of carnauba wax with high voltage. There was an article (in Popular Electronics?) back around 1970 that told how. https://www.youtube.com/watch?v=1DR-tTU8uIM _______________________________________________ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.