headlight & resistor

[jaijef]

Hello all,
I am installing a Digitrax decoder in my Athearn sd40-2.
I was trying to wire in a new headlight set up using 2 12volt Microlamps from RadioShack. These have 60mA. So I am using a 22K Ohm resistor like the Digitrax book says to use w/any bulb over 50mA. The bulb will light w/o the resistor but it will not w/the resistor after the resistor has been soldered.
Jaijef

Any help is appreciated.
sincerely
jaijef

 

[woodone]

After the reister was soldered? Does this mean that at one time the lamps did light up? Then after you soldered them - no lights? Bad solder joint could be the problem.
What voltage is being used?
I am not sure, but with DCC, the voltage is a square wave pulsed voltage.
That could make the resistor value wrong?

 

[Gary Pfeil]

22k seems like an extremely high value. In fact, if the lamp lights with the output of the decoder without a resistor, a resistor along the lines of 180 ohm should work.

 

[jaijef]

fixed problem

Thank you all for the replies.
I ended up using a 22 Ohm resistor w/a 60mA 12V bulb. after the soldering was done, everything worked great.
jaijef