HEADLIGHT VOLTAGE

[EARIC]

 I am putting a bachmann dcc decoder #44913 in my train and i need to know what voltage led to use do i use  a 1.5 or 12volt 
EARIC

[NMWTRR]

I assume you are running a DCC system.  Most of them put 12 volts on the track so you need an LED that can handle that voltage.

More details on your DCC system would confirm that.

Best of luck with the install!

[lmackattack]

all depends on the LED. I think Bachmann already has a resistor on the board to brink 12V down to what the stock LED needs.
If it currently has a LED  you may just be able to swap in a diffrent LED.
If it has a light bulb then yes it will need a resistor. IIRC you will need a 560 ohm resistor for your led to be safe

[EARIC]

Thank you i have 12volt led that are good up to16volt.
Thank's again
EARIC

[rayt]

Don't quite understand what do you mean.

The working voltage of a yellow led is about 2.5 - 3 volts, so if the supply voltage is higher then 3 volts, you will need a resistor to drop down the voltage, a 560 or 680 ohms resistor are both ok.

Raymond

[richg]

LED Resistor Values
Measured with 12.2 VDC supply using 20 ma max current LED's. Brightness increases some with more current.
A couple Spectrum locos I had that came with LED lights had only about 5ma because of higher resistance on the PC board for the LED which resulted in a noticeable dim LED. That may have changed by now.

Resistor      Current
1000 ohm    9.0ma

750 ohm     12.45ma

680 ohm     13.12ma

510 ohm     16.

Remember, LED's are current sensitive devices. Bulbs are voltage sensitive devices.

Link to LED info. Save in Favorites.

http://led.linear1.org/category/led-basics/

Rich