1975 Voltage Standard Restoration & "Improvement"? 😬 Fluke 731B 

😂

pp

I wask like, "Why is he calling it a stargate meter? I don't remember it in the show." That gave me a good laugh.

While I studied, i had some courses in electrochemistry. Its about dentrites growth. Sharp points on the surface have a higher electric field and therefor more material gets deposited on these points. Over some charging cycles these dendrites grow more and more, until they puncture the seperator or even touch the other electrode, shortening the battery. If you vary the charging voltage, dendrites growth can be minimised. Some experiments even used shifted fullwaves to charge the batteries, so in parts of the cycle, the battery gets discharged again, but it lengthens the lifetime of the battery

Ha ha ha, you hate the switch. I know why, and yours is rough, but for anything else they're gorgeous.

Can confirm, I also heard of pulse charging ni-cad's, but to stop tin whiskers and to stop the dreaded "memory effect". There's always some bullshit going with batteries, like compressing the crap out of lifepo4 cells. Sure, it can have benefits in certain applications, but like with pulse charging, if you aren't using it in that very specific application, it's pointless. But everyone will do it cause they saw someone else doing it, and then it becomes REQUIRED. 🙄

​@@sarahjrandomnumberstbf the lifepo4 manufacturers do (sometimes) specify compression as required or recommended. Though from memory it's a great deal less than what some are advocating

@@zyeborm When you do the math, for ESS usage, compression is pretty much pointless. 280ah full cycle every day is many years, then take into account you're not doing a full cycle a day, and that you're not hammering them at 1c, and shelf/storage life is more of an issue than compressing. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-OsvPYw6hoHc.html Again, compression is something that people saw in the datasheet, then the diy crowd went insane with it, just like pulse charging nicads. Compression can help in CERTAIN situations, but for the diy crowd, the cells will degrade naturally long before cycle life is an issue.

@@sarahjrandomnumbers Back in the day when I was hanging out in the college ham radio club, we used to "resurrect" old Motorola HT-220 batteries we got for cheap at the hamfest by "pulse charging" them with 15 or 20 amps with very short duration pulses. The theory was that we could zap away the whiskers that were internally shorting cells in the battery pack, without actually exploding the pack in the process. We did manage to avoid the exploding part, though unclear how successful that strategy was. But we were poor college students and that was cheap fun, flirting with danger.

I think the contact resistance of the wiper may be what is triggering him. I would also normally not care but due to the nature of this instrument I am ok with the replacement and choice of part.

If there's a base on there you will leave a salt residue. Vinegar by itself can leave solid acetic acid behind. I would normally suggest using a carbonate if there's an acid or a base to neutralize then follow up with several rinses to get rid of the salt that gets left over. Advantage of the carbonate is you don't care if it's acid or base and you can dump an excess of it on there and it won't cause additional acid/base damage.

allan bradley style carbon composition types yes, absolutely

To have firmer grip on reality, of course.

ppms is a highly addictive drug that has destroyed the lives of many brilliant electronics engineers

He uses them to test the voltmeters he needs to check his voltage standards, obviously.

Kind of Like when Rick showed Morty what true level felt like. And he was never the same again.

The pot and much of the other changes were for long term stability in the end, that is what his long term logging research is all about. At these accuracy levels everything as about stability. The exact value does not matter as you transfer the standards from one instrument to another and have to allow for some error so a bit more makes no difference.

16:52 😍 never seen one of those! Cool potentiometer.

LiFePO4*, "lithium-iron phosphate"

NiMH can be trickle charged at C/50 (0.02C) indefinitely

Second 😅

What's the difference you are hearing? I had a pretty loud device right next to while voiceovering this one and used some adaptive noise filter ... thought it was practically unnoticeable?

Might just be the tinnitus from a friend exploding a few (read as: literally 100) tantalum caps not far from my ear by accident messing with me, but it sounded a bit groggy to me, lol

​@@repsit sounded fine on my phone speaker but really messed up on my headphones. Can't really give you any more info than that sorry lol

he has just received a firmware update that improves his ability to imitate humans