My small N scale layout has 7 turnouts. I want to fit bu-colour LEDs to the control panel so that when a turnout is thrown the main line shows red and the branch shows green, when the turnout is thrown again the main shows green and the branch is red. The LEDs are wired through a switch under each turnout with a common positive. Each LED has 3 leads, one for red, one for green and a negative. The negatives are also common wired. The red lead of one LED is connected to the green of the second LED and vice-versa so that the two LEDs for each turnout are on all the time but showing either red or green depending on which way the turnout is thrown. My problem is that the reds are quite bright but the greens are dim. Is there some way I can get both colours about the same? I can operate on either 5V or 12V. On 5V the total draw for the 14 LEDs is about 300milliamps. If I put resistors on each LED it will affect both the red and green and even though the red might be a bit dimmer it would probably shut the green off completely. Does anyone have a solution please.
:You would need two resistors per led, one for the green and one for the red. Bi color leds have different specs and you must adjust each color. On a five volt supply you are in the range of 150 ohms. Try 120, 150, 180 or 220 ohms until you find one that suits. In the sititution you talk about you need 4 resistors per turnout.
Just use one bi-color LED for your turnout. Have the LED green when the turnout is lined for the main and red when it is lined for the siding. This is representative of what is done on actual railroad switch stands. A train traveling down a mainline will see a switch stands green target when the switch is lined for the main and will see the red target when the switch is lined for the siding. Of course there are some variations in the color schemes used by different railroads. Some use yellow instead of red.
Ned has the wiring correct.
I posted this topic and seem to have 2 replies but I can’ t access them. What do I do to read the replies?
Got the replies - somehow! Thank you ‘nedthomas’ and ‘ericboone’ . I thought I may have to use individual resistors for each colour and it seems to be so. Thanks again.