On Saturday 11 November 2017 05:24:30 andy pugh wrote: > On 11 November 2017 at 03:01, Gene Heskett <[email protected]> wrote: > > With Andy recommending about 10 mills, then I'd need 390 ohm r's for > > current limiters. > > Thinking about this further, are you sure there are no limiters on the > BoB? I can't imagine the ebay vendors exposing bare optos to the > clueless user?
You could be correct, I'll have to dislodge it from its resting place, but in that case, why did they not put a flea clip jumper on it to power the things. There isn't one, and docs on this thing are all but non-existant. If there are, I can put an interconnecting ground on it, and put 5 volts out to the switches common and let them switch the 5 volts to the input terminal. This board can be had for 4 dollars, probably with free shipping off fleabay. It was small and didn't have a bunch of gingerbread on it, just one small relay. No thru port etc. I'll investigate with a dvm and see if thats practical to do yet today. If thats the case, and I can verify a resistance between the input terminal and a leg of the moc, and a ground to that gnd terminal from all the other mocs, its a go. Or alternatively, an r of suitable value to one leg of each moc, and a dead short from the other leg on that side of the moc to the input terminal. The downside is that puts 5 volts straight from the supply out on those switches, which is not good engineering at all. Humm. I have +12, +24 regulated and around +35 unregulated, all available right in that box for relay coils etc, so a bigger r from a higher voltage could feed the switch common, with that higher R supplying a safety current limiting function in the event of a short. I like that idea. My coffee is obviously taking effect. :) Another cuppa and feed Dee, and I'll get legal for public viewing and go check. Thanks Andy, you triggered some thinking I wasn't doing well yesterday after tiring a bit. > > Anyway, another ten dollar assortment will be here in about 3+ weeks > > I guess. No wholesalers still exist that I'm aware of without a run > > to Pittsburg PA, about 150 miles north > > I suddenly feel rather lucky that I can cycle 5 miles to a shop that > opens even on Sunday and buy simple components ( > https://www.maplin.co.uk/c/components/electronics-components ) and get > almost anything else with free next-working-day delivery from RS > components. I'm jealous. Even 20 years ago my nearest source was in Fairmont, nearly 40 miles up the superslab.0 > On the subject of electronics, my cheap eBay hot air rework station > arrived yesterday. I have to say that it is far better than the £22 > asking price had me expecting. It made very short work of swapping out > some SOIC8 packages, though I did pull up some pads removing a 100-pin > LQFP. But then I doubt I could have ever got that off with an iron, > and I don't think the problem was any fault of the device. > > https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313. >TR11.TRC1.A0.H0.X858d.TRS0&_nkw=858d&_sacat=0 I've had an 853D (on down that page quite a ways) for a couple years, paid a lot more than that for it. It needs 2 improvements, first being an active retainer strap for the hot air hand piece, its always falling out of the holder, and another 3 feet of cord on the iron. When I'm using it on something inside my machinery's stuff, its a pita rigging something for it to sit on so the iron can reach to where the joint is. But it beats another similar unit that suffered a control board failure and no schematics or parts available and that I paid $209 for. It had a builtin air pump for the hot air thing that I may yet convert to solder sucker. Thanks Andy. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
