Jeff Liebermann wrote:


I also wanted to see how the
ESR meter functioned with small value and size (0.22uF 50v) caps,
which was Cap-D. The change in ESR with temp was far less radical
than the others.

** Even a 0.22uF film cap reads 7 ohms on the Bob parker meter -
IOW the impedance of the thing at 100kHz. Bob's meter does not
read actual ESR values, rather it reads impedance vales at 100kHz.

Right.

** Then you should not have posted what you just did. The actual change in ESR of a 0.22uF 50V electro was not readable on a Bob Parker meter.

What is really happening is the electrolyte becomes more conductive at higher temps, many times more in the range from 20C to 100C. It is the resistance of this fluid that dominates the ESR value.


A man has gotta know the limitations of his ESR meter.

I just hate reading the instructions.


** Right - you take zero notice of anything others tell you.




I wasn't interested in high voltage electrolytics.

** They have higher ESR values than low voltage caps, so there is
plenty of room for ESR readings to come down without approaching
the low reading limit of Bob's meter.

I used a value of 47uF, so its reactance at 100kHz was negligible.

Pays to think ahead, you know.

Yeah, but I think you missed my point.


** No I didn't.

You missed mine, as usual.


..... Phil