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Thread: How to tell if its AC or DC

  1. #1

    How to tell if its AC or DC

    Received some LED flood lights for Christmas. On checking the transformer from 240 to 12 volt,( constant voltage) I dissolved the lights we low voltage 12 V AC.
    In the mean time, I had ordered similar LED lights on the internet.
    After 3 months they turned up. These don't have the driver( transformer). They are 10 Watt each. I was expecting they would be DC, but now I am not sure.
    I checked the web, and searched 10 web sites. 9 of the ten, indicated they were 12V AC, and one indicated 12 V DC.
    I don't have an oscilloscope, so how do I tell if they are AC or DC?
    If I hook them up to DC, will I do any damage if they are in fact AC.?The model number is YK02104 made by OCOCO
    David

  2. #2
    Ausfish Gold Member 552Evo's Avatar
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    Re: How to tell if its AC or DC

    LEDs will work on both ac and dc.
    They are diodes and basically they act like a one way valve allowing voltage to travel in one direction and blocking the voltage in the other.
    The LEDs will contain circuitry (i.e. A resistor) to limit the current inside the housing.
    What do you mean when you say you checked the transformer and then you dissolved them ?
    Did you blow them up ?


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  3. #3

    Re: How to tell if its AC or DC

    Quote Originally Posted by 552Evo View Post
    LEDs will work on both ac and dc.
    They are diodes and basically they act like a one way valve allowing voltage to travel in one direction and blocking the voltage in the other.
    The LEDs will contain circuitry (i.e. A resistor) to limit the current inside the housing.
    What do you mean when you say you checked the transformer and then you dissolved them ?
    Did you blow them up ?


    Sent from my iPhone using Ausfish forums
    OOPs a typo on my part. When I checked the driver, a constant voltage type, it indicated 12 volts AC( first set of lights)
    second set has no driver( transformer)
    I will have to purchase the driver, but I cant be sure the second set of lights are 12 V AC, I need to find that out before I buy the driver..
    If I connect up the last set of lights to a 12 volt DC system, will they work in any case, or will I do damage.
    I understand that LED can work on either, but as an example, a 240 volt replacement bulb, has the driver is built into the bulb .
    I know that we are talking low voltage, but I have no information as to whether the last set of lights is AC or DC.
    If they are AC, I will need a step down driver( Constant 12 volt outlet). Constant AC adaptor show the out put in mA.

    PS I am on a big learning curve here.
    David

  4. #4

    Re: How to tell if its AC or DC

    Some LED lights are made to be just connected to 240, they have all the "stuff" built into a circuit board, but this applies to complete fittings of course, sounds like you just have replacement "bulbs"?

  5. #5

    Re: How to tell if its AC or DC

    wholesale-1pc-10w-12v-waterproof-led-flood.jpgModel YK 02104, Made by ICOCO
    Noelm,
    The lights are complete underwater IP68 flood lights, with a short lead. These need to be connected to a driver, but I need to know if the driver needs to be AC or DC.
    The driver supplies a constant voltage according to the requirement of the light unit. In this case 12 volt. But AC or DC. I suspect 12 v AC, but I need to prove that.

    The first set , which was a present ,came with the driver. The later ones don't. Below it indicates AC power source. 9 of 10 searches showed the same, one said DC
    David
    Features:
    LED underwater light is the perfect solution for decorative illumination
    water landscapes and illumination. With an IP68 waterproof grade, it is
    perfect for Swimming pool, ponds, fountain, aquariums, recreational facilities,
    decoration underwater, park lake, water stage and other outdoor place foratmosphere decoration

    Brand new and high quality
    Aluminum housing, good heat consumption, long life span.
    Application: Indoor cabinet, kitchen Lighting or decoration.

    Specification:
    light:warm, cool
    Power:10W
    Case color: black

    Input voltage:12V
    IP rating:IP68
    Material:Aluminum
    dimension:L82*82*110mm
    Beam angle:120°

    Package including:
    1x Underwater light

    Body Material: Aluminium Alloy LightSource: LED Model Number: YK02103-YK02104 Power: Others Voltage: 12V Protection Level: IP68 Style: Art Deco Finish: Brushed Nickel Is Bulbs Included: Yes Occasion: Square Certification: CCC Power Source: AC ItemType: Flood Lights
    · Brand Name: ICOCO
    · Item Type: Flood Lights
    · Style: Contemporary
    · Body Material: Aluminium Alloy
    · Model Number: YK02104
    · Finish: Brushed Nickel
    · Light Source: LED Bulbs
    · Is Bulbs Included: Yes
    · Protection Level: IP68
    · Voltage: 12V
    · Power Source: AC
    · Occasion: Square
    · Certification: CCC
    · Color: Black
    · Power: 10W
    · Beam angle: 120°

  6. #6
    Ausfish Gold Member 552Evo's Avatar
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    How to tell if its AC or DC

    Quote Originally Posted by dnej View Post
    OOPs a typo on my part. When I checked the driver, a constant voltage type, it indicated 12 volts AC( first set of lights)
    second set has no driver( transformer)
    I will have to purchase the driver, but I cant be sure the second set of lights are 12 V AC, I need to find that out before I buy the driver..
    If I connect up the last set of lights to a 12 volt DC system, will they work in any case, or will I do damage.
    I understand that LED can work on either, but as an example, a 240 volt replacement bulb, has the driver is built into the bulb .
    I know that we are talking low voltage, but I have no information as to whether the last set of lights is AC or DC.
    If they are AC, I will need a step down driver( Constant 12 volt outlet). Constant AC adaptor show the out put in mA.

    PS I am on a big learning curve here.
    David


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    Last edited by 552Evo; 27-02-2017 at 01:39 PM. Reason: Posted the same time as post above

  7. #7
    Ausfish Gold Member 552Evo's Avatar
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    Melbourne

    How to tell if its AC or DC

    Just saw your post with the specs above: we must have both post at the same time.
    I just read up about ac LED's and ac is used for specially built LED's over longer distances. The ac waveform functions better when cable length losses are factored in.
    This "driver" your talking of is just the power supply. I would just try the dc first ( I think it's safer for the test) then if that doesn't work try ac supply.






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  8. #8
    Ausfish Gold Member 552Evo's Avatar
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    Re: How to tell if its AC or DC

    How did you go dnej ?


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  9. #9

    Re: How to tell if its AC or DC

    If they are 12 volt then I am sure they will require DC, a quick check is the colour of the input wires (same colours will be AC).

    If they need DC and you only have AC available then duck into Jaycar and they will give you a suitable diode to drive the DC requirement.

  10. #10

    Re: How to tell if its AC or DC

    My apologies. Been off the air for several weeks.
    Yes,552 Evo, you are correct about LED s working either or AC or DC, on low voltage. I was interested to find out, so do incandescent bulbs. They just don't care. where they get the power
    The AC only uses half the current, as it cannot return via the diode,
    The on off situation is so fast, that it cannot be noticed, and no strobing can be noticed.
    That is something like movie making. A series of frames movie fast past your eyes.
    Most landscape lighting works on either AC or Dc, depending on the run length of the cable.
    Over supply of power on AC must be avoided., and the AC to AC constant current transformers are hard to find, where as the AC Dc ones are a dime a dozen.
    Funny thing is, I realized after a long while, that while the lights I purchased, indicated in most cases, that the power source was AC, I purchased them without the transformer, so the supplier was obviously recommending AC supply.
    I am about to hook up one to try now.
    I know AC handles longer cable run( Voltage drop), but I am now unsure which way to go. The DC system, say with a battery and a small Solar panel, may be my option. Any opinions on that
    Thanks David

  11. #11

    Re: How to tell if its AC or DC

    Gidday, just to finalise this post, I want to report on the results.

    The 10 watt, o.83 amp draw, LED light was connected to a 12 volt battery, pole sensitive, ( Neg to Neg ,Pos to Pos), and the lights worked beautifully.

    The I used a 240volt AC step down to a 12 volt AC, driver with max capacity of 1.7 Amps,

    Again with a positive result. No strobing could be noticed No need here to discern Neg and pos leads.

    So for best results on a longer run, use AC, and the voltage drop will be less.

    Now to find another driver of that same sort. 240 AC to 12 Volt AC. Or maybe I will go with a battery and a solar panel.
    What a great learning curve.
    David

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