Capacitor Leakage Experiments

RE: Capacitor Leakage Experiments

shabaz — Sun, 21 Jul 2019 12:52:36 GMT

Hi Jon,

Nice prototyping! Also the "Robust and Earthy" made me smile : )

Regarding the dual rails, I attempted using an off-the-shelf DC-DC converter visible in one of the photos here: Impact, Vibration and Ultrasound Sensing with PVDF Piezo Sensors

and stuck a metal shield between it and the circuit, and an LC circuit on each rail output to try to reduce harmonics from the DC-DC converter, but I didn't really investigate the output quality much at the time I think : (. Like your design, I needed some metal can around everything.

By coincidence I was working on building an amplifier circuit last night, a mic preamp, where I just used two 9V batteries, since they should last a very long time, and as you say, will be really good for eliminating power supply noise. Incidentally I was stumped for hours why there was audibly more noise than I hoped for.. turned out, the microphone cable (some off-the-shelf one I had lying around) was awful. Wire spiral shield, with very little copper : ( After it was replaced with a thicker braided shield cable, there was a world of difference!

EDIT: By the way, maybe humidity when breathing also causes an effect.. in some experiment a while back, capacitance changed measurably, for an air-spaced capacitor (I wasn't attempting to do that, but it was a side-effect). MLCC can degrade under high humidity apparently.

RE: Capacitor Leakage Experiments

three-phase — Sun, 21 Jul 2019 08:56:58 GMT

Very interesting experiments and test results to read through. Thanks for posting.

Kind regards.

RE: Capacitor Leakage Experiments

geralds — Fri, 19 Jul 2019 17:43:45 GMT

Fine Project!

What would you say, thinking about?:

I would spend a bit more parts for the UB- Voltage splitter. I think, that the voltages may swing a bit if you connect the testing device.

With an OPAMP it would be a bit more stabile.

Like this schematic, the 4. OPAMP of your schematic and a few parts plus.

The transistors and R3 may not be mounted, but if you need a bit more GND_Current,

because the CMOS_OPAMP can not spend this, the two transistors with that Emitter_R can be used.

[View:/resized-image/__size/321x223/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-f2d0f6e4-80a7-45eb-bbc5-b7c4b7e01314/contentimage_5F00_203953.png:321:223]

Best Regards

Gerald

---

RE: Capacitor Leakage Experiments

fmilburn — Fri, 19 Jul 2019 17:04:28 GMT

Hi Jon,

I really enjoyed reading this and learned a number of things. It is a delight seeing what you have done with the equipment and parts at hand.

Frank

RE: Capacitor Leakage Experiments

genebren — Fri, 19 Jul 2019 15:28:50 GMT

Jon,

Interesting data and setup. Sure it may be a little different, but that is the cool thing about electronics, there are several ways to approach any problem.

Thanks again for another deep dive with a fresh approach.

Gene

RE: Capacitor Leakage Experiments

dixonselvan — Fri, 19 Jul 2019 12:43:01 GMT

Interesting blog [mention:4f57fc9d538949ad9eb336ddb9469bb8:e9ed411860ed4f2ba0265705b8793d05] Jon Clift.

Any idea why your blog only fills half of the page? (refer below screenshot), I've checked other blogs and they fill the entire page. The screenshot has been taken in a chrome browser in desktop.

[View:/resized-image/__size/1036x478/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-f2d0f6e4-80a7-45eb-bbc5-b7c4b7e01314/contentimage_5F00_203951.png:1036:478]