Tuesday, July 19, 2011
Vintage Parts Excursion Part III: Building A Usable Capacitor Checker
After a few fits and starts and trips along a few blind alleys I managed to get the capacitor checker project up and running, and it's a pretty nifty piece of gear. This device will test capacitors for leakage in microamps and also can be used to reform electrolytics and check them for leakage. It has three ranges-10 ua, 1 ma and 10 ma. The meter movement is a 199 us Soviet military surplus job, and the cabinet's prior tenant was a Jackson 645 VTVM.
In the picture you can see a new old stock Mallory capacitor leaking about 80 ua of current and an orange drop Sprague showing about 1 ua of leakage, both at 350v. Also there's an electrolytic on the 10 ma range showing about 2 ma of leakage and it settled down after a while.
I've included two different schematics for devices of this kind.