I am building my first layout an having a great time. The layout system is DC. I have about 15 locos an would like to change all the headlights to LEDs. Knowing that LEDs run about 2.5 volts an the voltage to the track is variable, can any one tell me if there is a electronic circuit that i can build an install inside the loco to keep the voltage to the LED headlight at a constant 2.5volts. If there is , and i am sure there is, where can i find the electronic diagram to build one. I have looked at most of the MR hobby circuits but cant find it. Thanks . Dudrul…
Here is a constant voltage circuit for 1.5 v. If you go to an electronic supply house, they shouldbe able to give you a replacement bridge rectifier for the 2.5 volt output you want.
Generally LEDs run on 1.5V. The simple solution is to wire in a resistor that will have maintain 1.5V at the highest voltage your track can have. This means of course that the light will be dim at lower voltage. Constant track voltage is just one more benefit of DCC.
Hi
Check out linear tech or maxim. They are component manufacturers and make alot of DC-DC components. You may find a part with an Input voltage range from about 1.5v to 20v. Parts are available in tiny packages with plenty of current drive and could easily drive an led. Also since the input voltage range is so wide, and the output voltage is constant. A few support components may be needed, resistor and caps. Schematics and samples are normally available on thier websites.
Good Luck!