Power little LED with 110 Volt

Discussion in 'General Electronics Chat' started by SeeMyProfile, Mar 6, 2010.

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  1. SeeMyProfile

    SeeMyProfile Thread Starter New Member

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    Hello,

    I'm 60 years old but never will be too old to learn.

    I have a project where I'd like to use a small LED to indicate that there is power (110 volt AC).

    The light and resistor would be encased in a plastic resin compound which would hinder the removal of heat from the resistor, if any. I don't want a huge resistor in the circuit, a little one would be fine.

    Are there small LED's on the market designed for use at 110 Volt? If so, I can't find them.

    Could I use a small resistor in line before the LED so this little 1.5 volt LED wouldn't burn out? Is that possible?

    Sure could use some specific help here.

    Robb in Grand Rapids, Michigan
  2. beenthere

    beenthere Retired Moderator

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  3. Mike33

    Mike33 Senior Member

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    +1 You can even get them at Radio Shack; they're replaceable if burned out, easy to wire up a socket...they have advantages over the LED.
  4. eblc1388

    eblc1388 Senior Member

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    Yes, you can. But for AC usage a diode is required otherwise the LED will be damaged. Just about any diode like the 1N4148 can do.

    Just use a resistor of 100KΩ in series(roughly 1KΩ per volt) with the LED and a small diode in parallel. You would need to use "high efficiency" LED for this to work.

    So all together three components. As shown below.
    Last edited by a moderator: Nov 9, 2013
  5. phillipbeynon

    phillipbeynon New Member

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    The circuit can be very simple as there are several practical methods of design.

    I would suggest an NPN FET in series with an LED and gated with a resistor. That is 3 components. Any led can be used here. the important part is the amperage. Most LEDs require 20mA DC. Start by using very high resistors between the gate and negative lead of the LED and work it down until your meter across the LED reads 20ma.
    (Optional) Add a polar capacitor across the LED so it doesn't blink noticeably and 30hz
    Two advantages of this circuit is that you are controlling the amperage not the voltage and using a FET which reduces heat and it works for nearly all LEDs.
  6. spinnaker

    spinnaker Senior Member

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    Why are you answering a thread that is three years old? Chances are the OP has solved the issue by now.
  7. t_n_k

    t_n_k AAC Fanatic!

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    More importantly LED to mains is a restricted topic.
  8. #12

    #12 AAC Fanatic!

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    Hang on! This is a necropost, second one today.
    Reported.
  9. Bill_Marsden

    Bill_Marsden Moderator Staff Member

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    I have send the new user a PM, I am closing this thread since it violates our ToS.
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