Blog - All Comments

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

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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]

RE: Decoupling Capacitor Experiments

jw0752 — Sun, 23 Jun 2019 14:25:15 GMT

Hi Jon,

I like your creative approach to circuit board fabrication. I will have to try this some time. I enjoyed reading your experiment.

John

RE: Decoupling Capacitor Experiments

genebren — Sat, 22 Jun 2019 22:30:13 GMT

Jon,

Nice look at the effectiveness of decoupling capacitors! It is difficult to build the definitive test for decoupling, but your results do show the problem and the benefits of having decoupled supply lines. From worst case (none) to best case (10uF and 100nF), there is a reduction of the supply side glitch of 90%, which is a very good improvement. Had there been any inputs with higher impedance paths, or inputs held closer to their logic thresholds, you might have been able to see some mis-triggered output.

Nice work!

Gene

RE: Decoupling Capacitor Experiments

DAB — Sat, 22 Jun 2019 19:59:33 GMT

Nice post.

DAB

RE: Decoupling Capacitor Experiments

Jan Cumps — Sat, 22 Jun 2019 10:41:46 GMT

Philips! Virtually everything I touched when studying electronics was Philps. Components, power supply, oscilliscope, multimeters. signal generators, data books.

I'll try to redo this exercise with a modern low power logic device switching a high impedance load. I'm wondering (at low activity times in my life) if they still need decoupling.

RE: Your Mission Should You Decide to Accept it: Take My Polymer Capacitor Quiz and Pass It!

Fred27 — Wed, 20 Feb 2019 20:27:35 GMT

My prize arrived today. Thanks! I won't spoil the surprise for everyone else by saying what it is, but I like it. It has a sort of retro chic. [View:/resized-image/__size/16x16/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-41b6b038-c8d8-427b-852c-70e752bfd25b/contentimage_5F00_3.png:16:16]

RE: Ammeter Shunt FAQ

jw0752 — Sat, 26 Jan 2019 05:06:31 GMT

Just for the fun of it why not attach a data sheet if available for some of your shunts.

John

RE: Your Mission Should You Decide to Accept it: Take My Polymer Capacitor Quiz and Pass It!

luislabmo — Tue, 15 Jan 2019 18:52:27 GMT

Very challenging quiz but very entertaining questions.

Luis

RE: Your Mission Should You Decide to Accept it: Take My Polymer Capacitor Quiz and Pass It!

shabaz — Tue, 15 Jan 2019 16:26:07 GMT

I remember as a 9 or 10 year old my science teacher telling me about Mission Impossible being on TV.. and watching my first episode, it was awesome!

Later, my college was in central London, and I remember thinking there must be a passionate fan of the series nearby, since there was always a fancy car parked with the plate IMF 1, near the embassies.

The Polymer quiz looks very comprehensive and a nice challenge : )

RE: Your Mission Should You Decide to Accept it: Take My Polymer Capacitor Quiz and Pass It!

14rhb — Tue, 15 Jan 2019 16:22:11 GMT

I'm stuck at question 17 as there is no diagram (that I can see).

Rod