Re: 12 volts bulb and DCC


   You can use your 12 v lamp, actually any voltage less than track voltage. The trick is to install a resistor in series with it. I have a resistor substation box that makes it easy to find the right resistor. To find the value you need you need your bulb current. If it listed on the package just use the amp meter in your Volt Ohm Meter and use Ohm law. Make sure the wattage of your resistor exceeds the wattage of your bulb.
   I am partial to using Leds. The only problem with them is decoders that put out 1.5 volts which is too low for any diode. The do take care of the heat when you can use them.

On Thursday, January 8, 2015 11:11 AM, "dale.gloer@... [WiringForDCC]" wrote:

A 12 volt lamp connected to a DCC decoder will likely melt a plastic shell.  This is because the lamp is operating all the time at approximately 12 volts that is supplied by the decoder.  The reason it does not happen on DC is that the lamp seldom or maybe never operates on 12 volts - it operates on whatever voltage is supplied to the motor to make it run at the speed desired, maybe as low as 6 to 8 volts.  A locomotive on DC with 12 volts supplied will run at very high speed. 

In my opinion it is better to replace the lamp with an LED and suitable current limiting resistor when operating on DCC.  Some decoders are equipped with lamp outputs specifically designed for LEDs and do not require an external resistor.

Dale Gloer

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