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Discussion in 'General Electronics Discussion' started by dintence01, Dec 4, 2011.

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  1. dintence01


    Dec 4, 2011
    I have lights that are up to 5 volts dc, for my train set, they make the fire for the coal burning. I tried every light but they blow out. because my train set starts to run at 5 volts and goes to 16 volts and blows the lights :( I bought an adjustable voltage regulater from radio shack, the 3 prong adjustable 1.2v to 37 volts but I don't know about the wiring gram, I did electronics in school but kinda forget. I have resistors to do it but I wish someone could help me walk through it. My daughter thinks it can't happen and I don't wanna let her down that's why I came here for help. If anyone understands you can call me or email (also removed) [email protected] and if I didn't put the right oms or something maybe you know and can help me please. Thank you and God Bless.
    Last edited by a moderator: Dec 4, 2011
  2. TedA


    Sep 26, 2011

    We can try to help, but must start with some questions:

    Do you have a volt meter, or multi-meter of some sort? Do you have equipment for soldering?

    Do you think you will be able to work from a schematic diagram, or will you need more of a picture showing the wiring?

    Can you tell us more about the light bulbs you want to use? Is 5V indeed the voltage you want for them? How much current will one bulb draw at the desired voltage, and how many do you expect to light at once?

    You realize that the voltage regulator will only regulate the voltage down, and the most common ones require some fairly large minimum voltage drop across the regulator, before you can draw much current from it. So you may not get 5V for the bulb until the train's voltage reaches 6 to 7.5 volts.

    I'm guessing that the Radio Shack part is more than likely some version of the LM317, possibly in the TO-220 package, but we need to know for sure. There is a data sheet for the LM317 at:

    To work correctly, most such parts require a small capacitor on the input voltage, as well as the two resistors that set the output voltage. Although the application circuits usually also show a capacitor across the output voltage, this cap won't be of any help when the load is just a lightbulb, and can be omitted.

    BTW, where are you? This is an international forum! Your phone number looks like a North American one, but one cannot be sure.

  3. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    Jan 21, 2010
    The best advice comes from the datasheet. You don't specify exactly what device you have, but pretty much all of them follow the same rules.

    Have a read of that datasheet and see if you can figure it out. For driving a lamp, you can probably get away without either of the capacitors, but if you have some it would be better.

    You can adjust the voltage and your best bet is to adjust the output until the glow is right.

    If you have any more questions, please ask.

    I'm not going to call you because I don't have free international phone calls... In fact it's really bad to post your phone number, so I'll remove it from your post.
  4. dintence01


    Dec 4, 2011
    Hi Ted yes I'm in The states they say, Florida, hey thank you any i do have a volt metor and pretty handy with the solder iron, hey i can solder but what? You are the best, you said you can show me a diagram? I I'm sure I could follow it and do it and I'm sorry, Yes I'm international, I'm here in Florida and I wish I was there getting ****ed lol I don't know what part you are from but I know you are a good person!!! :)
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