[Lab] AC adapter question

[greg atcheson]

Your LEDs have a forward voltage of 1.6 volts and you are supplying 5
volts,  leaving 3.4 volts for the 91 ohm resistor. Ohms law: current =
volts / resistance. Plug in the numbers and you get 0.037 amps per LED,
much less than the 0.250 amps that the resistors are rated for. The total
current would be 7 amps, which is more than your supply is rated for.
On Jul 11, 2013 7:59 PM, "Britta Evans-Fenton" <technical at artengine.ca>
wrote:

> I'll check it out tonight or tomorrow morning, when I'm with my artwork
> again to be sure, but I think it might be even more than the 9 amps Michael
> suggests.
>
> How important do you think the other resistors would be. It would be a
> huge undertaking to re-do this piece.
>
> Here is the work here:
> http://brittaevansfenton.com/System_Failure.html
>
> Britta
> *Technical Coordinator *
> Artengine.ca
>
> Ottawa Mini Maker Faire
> Aug. 31 & Sept. 1 2013
> www.makerfaireottawa.com
> @MakerFaireOTT
> #MMFO
>
>
> On Thu, Jul 11, 2013 at 4:49 PM, Darcy Whyte <darcy at siteware.com> wrote:
>
>> Why don't you check how many amps you are using?
>>
>>
>>
>> --
>> Darcy Whyte
>> Twitter: https://twitter.com/inventor_Artist
>>
>> Art+ inventorArtist.com | Aviation rubber-power.com | Software Since '88
>> siteware.com | Contact: darcy at siteware.com | 613-563-3634 by appointment
>> | Canada N 45° 25'03.1" W 75° 42'21.4"
>>
>>
>>
>>
>> On Thu, Jul 11, 2013 at 7:41 PM, Britta Evans-Fenton <
>> technical at artengine.ca> wrote:
>>
>>> Maybe I'm drawing too much Amps.  Would you recommend this AC converter
>>> over the last one:
>>> http://www.digikey.ca/product-detail/en/LS150-5/285-1817-ND/1918828
>>>
>>> I would have Amps to spare on this one.
>>>
>>> Britta
>>> *Technical Coordinator *
>>> Artengine.ca
>>>
>>> Ottawa Mini Maker Faire
>>> Aug. 31 & Sept. 1 2013
>>> www.makerfaireottawa.com
>>> @MakerFaireOTT
>>> #MMFO
>>>
>>>
>>> On Thu, Jul 11, 2013 at 4:32 PM, Britta Evans-Fenton <
>>> technical at artengine.ca> wrote:
>>>
>>>> There are 188 IR leds:
>>>> http://www.digikey.ca/product-detail/en/QED233/QED233-ND/187410  All
>>>> connected in parallel each with their own Resistor ( 91 OHM 1/4W 5% CARBON
>>>> FILM)
>>>>
>>>> Britta
>>>> *Technical Coordinator *
>>>> Artengine.ca
>>>>
>>>> Ottawa Mini Maker Faire
>>>> Aug. 31 & Sept. 1 2013
>>>> www.makerfaireottawa.com
>>>> @MakerFaireOTT
>>>> #MMFO
>>>>
>>>>
>>>> On Thu, Jul 11, 2013 at 4:00 PM, Ken <klmckinnon at rogers.com> wrote:
>>>>
>>>>>  It should power a LOT of LED's.  How many were you using and what
>>>>> sort of current limiting resistor did you have....a quick circuit diagram
>>>>> would tell a lot.
>>>>>
>>>>> Ken
>>>>>
>>>>>
>>>>> On 7/11/2013 6:49 PM, Britta Evans-Fenton wrote:
>>>>>
>>>>>  A little question about AC adapters.
>>>>>
>>>>>  I have an artwork that I did that I used an AC adapter to get power.
>>>>>  It was on for 4 days during a show, and I was surprised on how hot it got.
>>>>>  (I almost burned myself).  I did have duct tape on it holding it to the
>>>>> back of a wall, so that may have been half the problem.
>>>>>
>>>>>  I'm showing the work again, but I'm wanting to make sure everything
>>>>> is safe.  I need to hide the adapter due to aesthetic reasons, so I wanted
>>>>> to create a little white box around it with air holes, and I was suggested
>>>>> a fan, although it if it getting hot due to over working, adding another
>>>>> fan might not be a good idea.
>>>>>
>>>>>  It is only a bunch of IR leds that it is powering, so I'm surprised
>>>>> at the power I am needing.
>>>>>
>>>>>  any help would be very well appreciated.
>>>>>
>>>>>
>>>>>  Here is the Adapter I used :
>>>>>
>>>>> http://www.digikey.ca/product-detail/en/VGS-25-5/102-1928-ND/2045659
>>>>>
>>>>>
>>>>>  Here are the IR LEDS:
>>>>>
>>>>> http://www.digikey.ca/product-detail/en/QED233/QED233-ND/187410
>>>>>
>>>>>
>>>>>  And the Resistors I have on them were 91 OHM 1/4W 5% CARBON FILM.
>>>>>
>>>>>
>>>>>   Britta
>>>>>  *Technical Coordinator *
>>>>>  Artengine.ca
>>>>>
>>>>> Ottawa Mini Maker Faire
>>>>> Aug. 31 & Sept. 1 2013
>>>>> www.makerfaireottawa.com
>>>>> @MakerFaireOTT
>>>>> #MMFO
>>>>>
>>>>>
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