I've got some BLMA signals that I want to start installing. You know, the ones "they" don't make anymore.
To save up my store of expletives, I want to test the LED's as I go.
That is, I want to test each signal out of the box. Then test each one during various installation steps.
What I strongly prefer is a battery-powered source to light them up, as opposed to using a VOM. There is something so reassuring and definite about seeing that.
I figure it's a simple matter of assembling some cells and a resistor.
I am seeking help on the number of cells (presuming 1 1/2 V) and the resistor.
All of this testing would be independant of the layout electrical--which isn't available at the moment--hence the simple and straightforward concept.
Thanks,
Ed
Nine volt battery and 1k resistor. Many here have done that. Most LED's are 20 ma max. No calculations needed unless you prefer the math method.
You cannot use a ohm meter to check LED's, at least I have never been able to do that. I have used a meter to check diodes but not LED's.
If you want to see the current reading, you can buy a tester off ebay for under ten dollars which ships from China. I was in a DCC forum where some bought a tester like this.
I use a multimeter, 1k resistor and nine volt battery. Slightly lower reading than using twelve volts. With twelve volts I have measure, 9ma.
My first VOM was a Heathkit one I put together in 1954. Lasted thirty years.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
I don't recall where I got this handy tester:
Yes, I know they're easy to make but this thing was around $10 and it clips onto a 9V battery and the mini gripper wire terminals are especially handy for the tiny signal wires.
Maybe it was Loy's Toys or Tony's Train Exchange? Anyway, I wish I had bought a few more
There's a bunch out there shaped like a tombstone. They're OK for testing a new LED with the leads still intact but for something with fine wires already attached they are not suitable to stick the wires into the little sockets.
If you make your own, I suggest you use these mini-grabber type clips. Very handy for all styles of LEDs and small wire.
I see LogicRail makes a "signal Tester" which could be handy.
https://tonystrains.com/product/logic-rail-st-1-signal-tester/
I would attach the test leads like Rich shows, below, to it. The screw terminals would be :Klutzy" at best.
Good Luck, Ed
I bought these many years ago. Cut some off and made my own test leads to use with my multimeters. Nice when working with components, DCC decoder wiring, etc.
http://www.apogeekits.com/images/smd_clip_test_leads.jpg
gmpullmanThere's a bunch out there shaped like a tombstone.
Those are for testing Darkness Emitting Diodes, or DEDs, to make sure that they, like Generalissimo Franciso Franco, are still dead.
I use a 9 volt battery, a couple of clip leads and a 1K resistor.
It takes an iron man to play with a toy iron horse.
MisterBeasleyThose are for testing Darkness Emitting Diodes, or DEDs
Oh! I thought they were for Life Extinguishing Die-odes
...and I have extinguished the life out of some LEDs, too
Thanks, all, for some very useful information.
I seriously don't want to keep installing a signal if it's not going to work.
And I am freely admitting that I will likely be the cause of the problem.
Found it!
http://www.ngineering.com/other_cool_tools.htm
Some signal systems use common anode LEDs while others use common cathode.
http://www.dccwiki.com/Signaling
The tester will help sort that out for you...
Neat.
other Ed
I found another signal tester: Logic Rail ST-1.
https://www.logicrailtech.com/xcart/home.php?cat=274
I can connect all four wires to it--there's a slide switch that will light each color.
Thanks again for your help,