Alan Douglas wrote:
The Fluke is the way to go for measuring capacitance of new parts. Now whether its reading is affected by leakage, I don't know. You can find out by measuring some ordinary capacitor, say 0.1µF, and then shunting it with a 1 meg resistor and seeing if the readout changes.
You don't normally need to measure capacitance of an old leaky paper cap (they're marked on the case), but if you did, and if the Fluke gave erroneous readings, the old GR 650 could do it. The Sprague might do it; I don't know offhand. The Sprague will definitely measure the capacitance value of leaky electrolytics; that's what the "power factor" dial is for. That's equivalent to the "D" (dissipation) dial on the 650.
Just as an aside, the GR and Sprague may give different readings, as the Sprague measures at 60Hz and the GR measures at 1 kHz.
With electrolytics, leakage current at working voltage is a concern. The Fluke is of no use for this, nor is the GR 650, but the Sprague will apply a variable DC voltage, while reading the leakage current on the meter. It may indicate lower values of leakage on the magic eye; I don't recall. You can use the Sprague to reform old electrolytics (if you consider it worthwhile or safe; that's another whole discussion that has been covered here at great length).
then that settles it, I must keep all 3
now to tell becky our ebay listings are going to be a little shy this week.
and thanks for the info,I have learned more on this board in a few days then what should be aloud ,