Re: Cheaper ESR meter

Alrighty then - Almost 2 months later and it is all in a box working and useful. Changed to a smaller 0-1v meter, but can see that .05 ohm target ... about 3 needle widths off full scale on the lower scale. Added an extra range - switch to the right selects on the meter scale. Upper-right corner is the 'short' indicator. Binding posts to the right are to attach to a bench supply vs the coaxial wall wart connection above it.

Hand drawn scale! But will finish when a minor problem ironed-out, like a slight op amp offset problem. The zero adjust...

Re: Cheaper ESR meter

Hi Gang. I have just been working with a protoboard prototype of this ESR meter. It works great per the original article. Have made a few modifications such as using a pair of TL082s (virtual ground source and oscillator in one and the rest in the other), along with mods to expand the range down to .05 ohms (not yet determined, exactly). However, the pair of 22 ohm resistors can be changed to 10 ohms each in the bridge with good results. Using a GIANT 200uA meter that also helps tremendously. I have used the oscilloscope method for years to match capacitors...