LOL! You people have to spend one hundred dollars in gadgets like the DE-5000 to measure ESR?
As a professional electrical engineer with large experience in the design and development of complex electronic hardware and firmware, I enjoy the use of my ONE RESISTOR ESR meter (see my previous post).
I measured (for fun) in 10 minutes the ESR of about 10 electrolytic capacitors mounted on a dual preamplifier board that is over 40 years old.
- I clipped the ground of the oscilloscope X1 probe on the negative of the electrolytic, and the probe on its positive.
- I clipped to the ONE RESISTOR of 1000 ohm a 10V positive 100Khz signal from my function generator (with the same ground as the oscilloscope), and touched with the other lead of the resistor the positive of the capacitor under test. The resistor became in fact a current source.
- I observed on the oscilloscope, set to 10 mV/div, the 100Khz signal in the equivalent scale of 1 ohm ESR per division. I found some good capacitors and many bad ones! (its amazing how well an amplifier can work even with some "bad" electrolytics...)
It could not be easier!