I have a question regarding the differences between leakage current testing a film capacitor and a ceramic capacitor. I have a test setup that outputs leakage current ratings utilizing a picoamp meter. I am measuring down to the nA range for leakage on a multitude of various capacitors. The ceramic capacitors are showing a fairly steady readout on the instrument 20-25nA. When I place a film capacitor inside this setup the meter is very jumpy and not outputting usable figures for leakage.
The thing is, I have tested all of these film caps on an I.R tester (which is what we typically specify these capacitors to) and when converted from I.R to leakage current they should be in the lower 10-15nA range. Why does this test setup show so much jumpiness with the film caps, even though they should be superior in leakage current ratings? Someone else is request leakage current ratings for a capacitor and they are also experiencing this jumpiness when they are testing on their leakage current setup. So we are both scratching our heads.
I have tested different film caps as well. Dielectric material, capacitance value, voltage rating, metalized and non-metalized,. All of them show this jumpiness. I conducted a 3 minute discharge test to verify these conversions as well. They are within 10% of expected voltage drain calculations. 1200V charge and a drop of 15V after 3 minutes. Expected drop calculated at ~12V.
Any insight into why this method of testing leakage is not consistent would be appreciated. Or suggestions on alternate leakage testing setups or equipment would be appreciated as well.
The thing is, I have tested all of these film caps on an I.R tester (which is what we typically specify these capacitors to) and when converted from I.R to leakage current they should be in the lower 10-15nA range. Why does this test setup show so much jumpiness with the film caps, even though they should be superior in leakage current ratings? Someone else is request leakage current ratings for a capacitor and they are also experiencing this jumpiness when they are testing on their leakage current setup. So we are both scratching our heads.
I have tested different film caps as well. Dielectric material, capacitance value, voltage rating, metalized and non-metalized,. All of them show this jumpiness. I conducted a 3 minute discharge test to verify these conversions as well. They are within 10% of expected voltage drain calculations. 1200V charge and a drop of 15V after 3 minutes. Expected drop calculated at ~12V.
Any insight into why this method of testing leakage is not consistent would be appreciated. Or suggestions on alternate leakage testing setups or equipment would be appreciated as well.