Recent content by jeeep1

  1. J

    LED power

    Okay, so If I use a 12VDC power supply with a 450 Ohm resistor (using 20mA) in series with one 3V LED everything will be fine then? (12V-3V)/20mA = 450 ohms (or the next highest standard resistor) See, for some reason, I have always thought that the 3V was all the LED could handle. But now its...
  2. J

    LED power

    Heres what I have: 12VDC Supply Voltage 3VDC Voltage Drop 20ma LED Current I used to think that the Total LED Voltage Drop should equal the Supply Voltage. But after doing some research I found that the Total Voltage Drop should be less than 80% of the Supply Voltage. So the correct circuit...
  3. J

    12VDC @ 100ft from source

    Omni, thank you very much for your post. It contained everything a perfect reply should consist of: an explained solution, an example with insite, and a interesting/relevant footnote.
  4. J

    12VDC @ 100ft from source

    I need to light a cluster of leds at varying distances; 50ft, 75ft, 100ft. The cluster of leds would be atop of an antenna and at the bottom would be several switches that controls the cluster. Idealistically, I would like to have 24VDC at the bottom of the antenna and then step the power down...
  5. J

    12v power supply?

    Ian, What I would do is get several old phone chargers. Lets say you have two phone chargers that puts out 6Vdc each. Take the positive from one and the negative from the other and check the remaining leads, which should equal 12Vdc. The power source doesnt have to be strickly old phone...
  6. J

    switching 12Vdc with 3Vdc

    Found a relay in my junk pile that should work, only thing is I cant figure out how to hook it up! I've tried searching google but no luck. Here is a diagram of the relay (from the bottom) This is what I'm guessing: 2 attaches to the +12Vdc 5 attaches to the -12Vdc 1 COM attaches to +3Vdc 4...
  7. J

    switching 12Vdc with 3Vdc

    Thank you esp1, that makes perfect sense. Is there a particular relay you can recommend that will handle 12Vdc @ 1amp?
  8. J

    switching 12Vdc with 3Vdc

    I have an AVR who's pin outputs 3Vdc. I would like to be able to turn on, or allow to connect, 12Vdc with this 3Vdc output. There will be two power supplies. What sort of electronic part am I looking for? Thank you
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