I will shortly be fitting DCC decoders to some older diesel locos, to which I will also be fitting headlights with leds.
What is the voltage output from the decoder on the yellow, white, green and purple wires so that I can fit white light leds with the correct resistors?
I will not be fitting red rear lights as the trains will be fixed formation goods trains.
Thanking you in anticipation for your answers.
Decoder output voltages
- Ironduke
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Re: Decoder output voltages
The blue wire is positive and never more than the supply voltage on your rails (so could be from 12V up to 18V on some systems). Just say 12V.
For a bright white LED at full brightness the recommended resistor value at 12V is 560R generally, but I usually use a 1K resistor. Use an even higher value if that is still too bright.
For a bright white LED at full brightness the recommended resistor value at 12V is 560R generally, but I usually use a 1K resistor. Use an even higher value if that is still too bright.
Regards
Rob
Rob
Re: Decoder output voltages
Hi Johnco
Absolute maximum voltage should be below 27V at extreme, and 24V in normal operation, but typically expect to see around 19V down to about 14V on most systems.
You will probably want to experiment a bit with resistor values as many modern LEDs - especially white ones and others derived from blue, will be very bright indeed when run at full power.
Suzie x
Absolute maximum voltage should be below 27V at extreme, and 24V in normal operation, but typically expect to see around 19V down to about 14V on most systems.
You will probably want to experiment a bit with resistor values as many modern LEDs - especially white ones and others derived from blue, will be very bright indeed when run at full power.
Suzie x
Re: Decoder output voltages
To give an example with a job I recently did on lights for one of my diesels, I used between 20K and 50k resistors depending on colour to get the lights dimmed down to realistic levels.
Pete.
Re: Decoder output voltages
There should be a recommended resistor value to use with the LED for nominal 12V operation. Most (all?) decoders offer output trimming for the auxiliaries, and it is usually possible to dim LED's satisfactorily in this way. (It can be worth trying '0' even if it is not specified as part of the operating range, all electronics leak.) Typically the value for a 'dim' light will be somewhere between 0 and 5 on a decoder offering 255 step output range. I also make a lot of use of 'Pentel' permanent markers to tint LED outputs in addition, simple to get the colour of warm incandescent filament lights, as used on BR's early diesels.
Re: Decoder output voltages
As Bigmet knows, Zimo decoders and maybe others can dim every lighting FO individually, but I took RJ's advice and used resistors of suitable values on each output so that if I ever have to reset the decoder for any reason I don't have to go through resetting all the dimming values.
I must have a look for those Pentel markers to see if I can buy them out here. Thanks Bigmet.
I must have a look for those Pentel markers to see if I can buy them out here. Thanks Bigmet.
Pete.
Re: Decoder output voltages
Edit: I see I can get them here, I think they're worth a look.Peterm wrote:As Bigmet knows, Zimo decoders and maybe others can dim every lighting FO individually, but I took RJ's advice and used resistors of suitable values on each output so that if I ever have to reset the decoder for any reason I don't have to go through resetting all the dimming values.
I must have a look for those Pentel markers to see if I can buy them out here. Thanks Bigmet.
Pete.