A Crummy Commercial

Renogy made this 10 watt solar panel bought this year: https://wb9kzy.blogspot.com/2026/03/solar.html so as was mentioned yesterday: https://wb9kzy.blogspot.com/2026/05/32-diodes.html lets look at the leakage current involved.  As with the UPG solar panel from yesterday, I waited until dark, then covered the panel and measured the battery voltage and the battery to solar panel leakage (discharge) current: 12.84 volts but ZERO current, there must be some kind of low leakage circuit inside the Renogy panel ? I didn't bother to count the lines (diodes) on the Renogy, counting gets tedious after a while and also this panel seems to be different.  But the specs are almost identical: The problem with having the nice cables and clips is that I hate to cut them to add a diode but since there is no leakage, no cutting required, nice ! Best Regards, Chuck, WB9KZY http://wb9kzy.com/ham.htm

I was thinking about the series blocking diode addition to my recent solar panel purchase: https://wb9kzy.blogspot.com/2026/04/make-or-buy.html Certainly there is a drop across the diode when the panel is charging, less than 250 mV with low current.  But is it really needed ? Looking at the solar panel itself again there are 6 wafers, each wafer has 6 groupings of photodiodes with 6-5-5-5-6 diodes each or 32 total diodes in series. count the wider horizontal dark lines to determine the number of solar cells   Per Wikipedia the output voltage of a silicon solar cell (diode) is .5 to .6 volts.  Multiply 32 diodes times .56 volts gets to roughly 18 volts which is about the rated voltage: 21.6 volts divided by 32 is .675 volts so this sounds reasonable for a no-load situation. Now since the panel is charging a lead acid AGM / gel-cell battery the highest voltage that the battery could apply to those 32 diodes is roughly 13 volts: source:  https://voltagebasics.com/lead-a...

looking at this EDN Design Idea :  https://www.edn.com/custom-diy-dmm-smd-fixture-for-low-z-measurements The thing that caught my eye was the clamp - the article calls them: Lever arm-toggling ?  Really ?  In the olden days of the 1970s/80s/90s we called them: De-Sta-Co clamps because that's what was stamped into the clamp  :)   I imagine that there are many generic versions now.   In our receiving inspection department they were used for holding a device-under-test (DUT) in place on a test fixture.  With ICs this wasn't necessary but with other items it was required to hold the DUT in place to minimize affecting the temperature or whatever.  https://www.destaco.com/clamping/manual-clamping/hold-down-clamps Where did we get them ?  why here: https://www.mcmaster.com/products/destaco-clamps/ I wonder if Destaco ever considered doing what Louboutin did with their shoes - Destaco clamps always had red handles :) https://en.wikipedia.org/wik...

I was looking at this patent: https://patents.google.com/patent/US8774317B2 it *appears* that it's not in force ?   Otherwise if it was still in force it would run until 2032 as I understand it. Everset is the company that got the NIST to change the modulation of WWVB, adding BPSK to give better coverage in weak signal areas. This has never caught on, must be the cost ?  Two antennas are used with the Everset - the only clock I could find using the Everset chip is this one from Lacrosse: https://www.ebay.com/itm/388836130899 A video on the Ultratomic clock: source:  https://www.youtube.com/watch?v=wqJA7hVym90 two interesting points from the video:  first, the Ultratomic clock uses two (or strangely four) C cells rather than the single AA cell in most "atomic clocks".  C cells are harder to find than AA or D cells but a big point for me: Energizer doesn't sell lithium primary cells (leak proof) in C size.  So that's kind of a deal cruncher for me - I need th...

I bought another solar panel since this one: https://wb9kzy.blogspot.com/2026/03/solar.html This second one has similar specs and cost about the same but it was just a panel.  It didn't come with all the little cables and clips. I like solar panel specs, right on the back, easy to test, nice ! One thing I added was a series diode to prevent the battery discharging through the diodes of the solar panel at night.  I might change out that diode later for a MOSFET circuit but I'll have to research that to see what the pitfalls might be.  One problem is that the solar panel puts out 18 volts or more in full sun and that much voltage would probably zap the gate of a MOSFET.  So a circuit is required to protect the gate.  Another thing is that as I've encountered before, MOSFETs can conduct in both directions (unlike a diode).  So maybe it's best to just live with the voltage drop across the diode for now. The other thing I'll need is a cable which can easily be c...

The story that keeps on giving: source:  https://www.youtube.com/watch?v=eKlOY5wPS9U Milwaukee Journal article from 10 years ago:  https://archive.jsonline.com/news/milwaukee/15-minutes-of-fame-for-welcome-to-cleveland-sign-lasts-37-years-b99627742z1-360471381.html/   Every time a local Milwaukee TV station, newspaper or a blogger somewhere finds out about the story it lives again - I love it !  There's too much serious in the world but not enough silly.   If you punch "welcome to cleveland" into Google it'll take you to this: Best Regards, Chuck, WB9KZY http://wb9kzy.com/ham.htm 

After using the lamp for negative copying a while (mentioned here):  https://wb9kzy.blogspot.com/2026/04/new-lamp-for-negative-and-slide-copying.html I started to get tired of having to lean over to turn off the power at the wall socket.  So I broke out the old sheet metal punch and added a little C&K 7201 switch (also a ground screw): Here it is with the lamp ON: This should be a lot more convenient.  The now unused Leviton 1470 outlet switch at the lower left seems to be expressing alarm :) Best Regards, Chuck, WB9KZY http://wb9kzy.com/ham.htm