You can find the same thing at Ax Man Suplus. :) > On May 17, 2019, at 2:23 AM, Rick Engebretson <eng at pinenet.com> wrote: > > As an old dummy, I would go to Goodwill or a junkyard and get a good looking old radio amplifier to salvage. IIRC, the volume control is a reasonable wattage wire wound variable resistor. It would also give you a box. > > The landfills are getting full of valuable, re-usable electronic components. > > Wayne Johnson wrote: >> Just remember, 50% of the people are under average intelligence. >> >> If you really want to make a fancy battery tester, create one with a >> microprocessor that runs the battery through various load levels, then >> displays the resulting voltage as a graph on an LCD display. >> >> --- >> Wayne Johnson, | There are two kinds of people: Those >> | who say to God, "Thy will be done," >> | and those to whom God says, "All right, >> | then, have it your way." --C.S. Lewis >> >> >> ------------------------------------------------------------------------ >> *From:* Mike Miller <mbmiller+l at gmail.com> >> *To:* TCLUG Mailing List <tclug-list at mn-linux.org> >> *Sent:* Wednesday, May 15, 2019 11:01 PM >> *Subject:* Re: [tclug-list] [OT] where to get a 100-ohm resistor? >> >> This is really helpful. It answered a bunch of questions I had but hadn't >> asked. People were commenting on that YouTube battery-testing video that >> a 100-ohm resister wouldn't be right for a D battery, but I guess it also >> wouldn't be right for a 9-volt. >> >> Looking at more info out there on the web -- it's a problem for me that a >> lot of people don't seem to know what they are doing, but they are still >> there, teaching the world. ;-) >> >> Thanks again, Doug. >> >> Mike >> >> >> On Sun, 12 May 2019, Doug Reed wrote: >> >>> Yes, the Ax-Man stores are the place to look if you don't want to ask >>> someone to mail it to you. I believe there are 3 or 4 stores around >>> town. The only stores I am familiar with are in St Paul and Fridley, but >>> I thought there was one more in Bloomington. >>> >>> The color code for 100 ohms is brown-black-brown. But 100 ohms is too >>> low for testing a 9V battery. 100 ohms is fine for testing 1.5 volt >>> batteries at about 15 milliamp current load which is within the >>> capability of all AAA or larger batteries. >>> >>> But 100 ohms will attempt to draw about 90 milliamps from a 9V battery. >>> Most 9V batteries are rated for 50 milliamps maximum load. Your 100 ohm >>> resistor will tend to suck them down so they all fail your test. For a >>> similar test effect, you should use a 1000 ohm resistor, perhaps even >>> higher, up to 3000 to 5000 ohms so the load is proportional to the >>> battery capability. >>> >>> So when you are looking for the resistor at Ax-Man Surplus, the 100 ohm >>> resistor should have Brown as the first band, black or brown or red for >>> the second band, and Brown again for the third band. The bands are >>> counted with the first band closest to one end. >>> >>> The 1000 ohm resistor would have the third band colored Red instead of >>> brown. Since we don't care exactly what the value is between 1000 and >>> 5000 ohms, the first band can be any of Brown or Red or Orange, or >>> Yellow, and we don't care at all about the second band color. >>> >>> And I suggest that you look for a resistor that handles one-half watt >>> dissipation or more. Your batteries should never approach that but the >>> larger physical sizes are usually less likely to break from lots of >>> handling. A half watt resistor is physically about 1/8" diameter and >>> 1/2" long with leads about 1.5" on each end. >>> >>> The size you pick isn't really critical, it is really just for ease of >>> handling. You will probably find multiple examples to choose from, I >>> just suggest you don't choose the smallest size you find. Any resistor >>> larger than 1/2 watt will also work of course, if that is what you find >>> or want. The much larger watt values usually have the resistor value >>> simply printed on the side. >>> >>> And of course buy more than one of each for when you break or loose one. >>> :-) >>> >>> Good luck. If my description isn't enough to work from, you can easily >>> find web pages that explain the resistor color code. And you can always >>> bring your voltmeter to the store and use it to check the resistor value >>> before you buy. Or buy a handful of different values that have brown or >>> red on the third band and check them at home. No matter what you choose >>> to do, the parts will probably cost less than the gas to get you to the >>> store. >>> >>> Doug Reed. >>> North St Paul. >>> >>> -- >>> Scientists say the world is made up of protons, neutrons, and electrons. >>> They forgot to mention MORONS. >>> >>> She had buried three husbands and at least two of them had already >> been dead. >> _______________________________________________ >> TCLUG Mailing List - Minneapolis/St. Paul, Minnesota >> tclug-list at mn-linux.org <mailto:tclug-list at mn-linux.org> <mailto:tclug-list at mn-linux.org <mailto:tclug-list at mn-linux.org>> >> http://mailman.mn-linux.org/mailman/listinfo/tclug-list <http://mailman.mn-linux.org/mailman/listinfo/tclug-list> >> >> >> >> >> _______________________________________________ >> TCLUG Mailing List - Minneapolis/St. Paul, Minnesota >> tclug-list at mn-linux.org <mailto:tclug-list at mn-linux.org> >> http://mailman.mn-linux.org/mailman/listinfo/tclug-list <http://mailman.mn-linux.org/mailman/listinfo/tclug-list> >> > _______________________________________________ > TCLUG Mailing List - Minneapolis/St. Paul, Minnesota > tclug-list at mn-linux.org <mailto:tclug-list at mn-linux.org> > http://mailman.mn-linux.org/mailman/listinfo/tclug-list <http://mailman.mn-linux.org/mailman/listinfo/tclug-list> -------------- next part -------------- An HTML attachment was scrubbed... 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