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Model Railroading > are there any 1.2 v , 15ma sub miniature bulbsDate: 04/16/14 20:17 are there any 1.2 v , 15ma sub miniature bulbs Author: fbe Those voltage regulator ICs give an 1.25v output. I find the 1.5v bulbs a but dim especially when mixed with leds. So are there any 1.2v bulbs I might try?
Thanks. Posted from Windows Phone OS 7 Edited 1 time(s). Last edit at 04/16/14 21:52 by fbe. Date: 04/16/14 21:06 Re: are there any 1.2 v , 15ma sub miniature bulbs Author: NDHolmes You could also just bump the regulator up a bit. Given you mention 1.25V out of a regulator, I'm assuming you're talking about an LM317. It's easy to set it for 1.5V - 240 ohm resistor from the output to adjust pin, 56 ohm resistor from adjust pin to ground.
Date: 04/16/14 21:29 Re: are there any 1.2 v , 15ma sub miniature bulbs Author: fbe Here are the circuit references for the ICs.
http://www.tonystrains.com/technews/install-lamps-decoders.htm http://www.mrdccu.com/curriculum/lighting/1.5Volt.htm Down towards the ends of each there are the circuit diagrams and they do seem to be the LM317 IC. What is the ground for the 56 ohm resistor connection to the adjust? Thanks. Posted from Windows Phone OS 7 Edited 3 time(s). Last edit at 04/16/14 21:51 by fbe. Date: 04/17/14 18:46 Re: are there any 1.2 v , 15ma sub miniature bulbs Author: barrydraper Neither one of those links shows a true 1.5 volt supply, but at the bottom of this page there is one: http://home.cogeco.ca/~rpaisley4/PSupply.html
The design is for a wall-powered supply, with DCC the blue wire is the 12 volt source and you could eliminate the three capacitors. The negative return could be the the function "output" wire if you build a separate regulator for each lamp, or you could use the ground wire if the decoder has one (usually black/white). Barry Draper |