On a lark I ordered one of these: http://www.goldmine-elec-products.com/prodinfo.asp?number=G17170 About 30 Vactrols in it. A few quick measurements: Sample #1 Ifwd = 0 mA : Rout = 6.7kohm Ifwd = 7 mA : Rout = 300ohm Sample #2 Ifwd = 0 mA : Rout = > 10Mohm Ifwd = 7 ma : Rout = 200ohm Seems pretty variable. Any use for these? Eric