BC107

Problem Sorted..!!! It seems the over reading was caused by the leakage inductance of the transformer, where the capacitor partially resonates with the inductive component to give a greater current than the short circuit. Many thanks to 'Jimmc' from EEVblog for this insite. This has now been turned to my advantage by including the best value NON polar polycarb cap in series with the capacitor under test as a permenent mod to my meter. Many thanks to all for your comments, Cheers

Hi Hero999, yes I see your point I assumed only people interested in ers meters would answer, where Ludens circuit would be well known. Anyway I though "How are we supposed to know?" was a bit cryptic, where it could have been "How are we supposed to know? unless you show us the circuit!"..! Anyway I get your point, I'll be more detailed in future posts Cheers

Well i'm aiming my question at electronic engineers with some 'mature' experience to reply, sorry if I missed the mark.! (with you)

Hi I'v just finished an ESR meter based on Ludens simple analog circuit, which seems to work very well. I did a small mod to broaden the range a bit, so 4.7 ohm is below mid scale great. Works fine. Here's the Puzzle!. I short the test leads out to zero the meter fine. Then If I measure a 'NON Polarized' 1.5uf polycarb capacitor it takes the meter about 5mm Past the zero point!, It also goes over the zero on another 2.2uf non polar cap I have? How can this be?. If a short circuit limits the meter to Zero FSD. how can measuring a non Polar cap send it further over the Zero? As for electrolytics the meter works fine. Any Info would be much appreciated. Thanks all