using leds with a power arcade supply?

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    • using leds with a power arcade supply?

      hi, ì`m trying to figure out how to use leds with an arcade power supply, but the leds just support 20mA and the lowest current from the PSU is 2,5A from 12V. How could i find a resistor good enough to low both current and tension to 3,3v and 20mA? I can`t figure out a way to low the current to that. Besides, i`m trying to use 3 leds. I must associate them in parallel to maintain the same voltage that i need(3,3v), isn`t it?
    • Formula: R = (Vs - Vf) / If

      so...

      (12-3.3) / 20 = 435ohm resistor, so round up to next highest resistor available if that rating is not available.

      Why are you using the 12 line? You could use the 5v if you want and just recalculate with the formula above.
      Multis: CPS2│CPS3│ST-V│F3│GNET│TTX2│NAOMI
      Superguns: Jasen's MK30ADCAP│RGB's HASv3
      MB: NAOMI 1,2│MV-1FZ & MV-4│IGS PGM│SEGA ST-V│TAITO F3│TTX2,X3
      CAPCOM CPS*│RINGWIDE/RINGEDGE 1, 2│HYPER 64
      LINDBERGH Y/B|IREM M*|CAVE (ALL YOUR BASE)

      +++
    • TheBortot wrote:

      But @Derick2k , when u use the formula, u have to put 20 x 10^-3, instead of just 20, cause it`s 20mA, not 20A, isnt`t it? Besides, i thought about the 12v line because in the 5v, the current is 15A. I tried to use a 1k potenciometer in the last one, but it burnt when i reached 3,3v.

      Ohms Law & Decimal points dude!

      (12-3.3)
      =
      8.7
      ÷
      0.02
      =
      435
      Ohms
      Vs + Vf
      20ma in Decimal
      = .02



      But hey, dont take my word for it (I only have lowly degree in EE), here you go:

      led.linear1.org/1led.wiz?VS=12;VF=3.3;ID=20
      If its on the internet it has to be true ;)

      As that online calculator suggests, go with a 470 ohm 1/2 watt resistor and you will be fine.

      I suggest you read up on Ohms Law, it will clear things up.
      In simple terms Voltage drives current, so I=V/R, so no need to worry about using the 5V line, using a 5V supply with the above formula calculates to an 85 Ohm resistor so use something like like 100 Ohms.
      Multis: CPS2│CPS3│ST-V│F3│GNET│TTX2│NAOMI
      Superguns: Jasen's MK30ADCAP│RGB's HASv3
      MB: NAOMI 1,2│MV-1FZ & MV-4│IGS PGM│SEGA ST-V│TAITO F3│TTX2,X3
      CAPCOM CPS*│RINGWIDE/RINGEDGE 1, 2│HYPER 64
      LINDBERGH Y/B|IREM M*|CAVE (ALL YOUR BASE)

      +++

      The post was edited 3 times, last by Derick2k ().

    • i think i was lazy at calculating and i just saw u using 20, sorry! I know the law, but i didn`t know i could just make a difference at different potencials. Nah, don`t bother with EE, i guess arcade life taught u very well. Thx for the patience and for teaching me.
      Ok, here i go waiting for parts coming from post office...hate this part.
      Besides, i should bother with 1/2 or 1/4 W heat dissipation?
    • TheBortot wrote:

      i think i was lazy at calculating and i just saw u using 20, sorry! I know the law, but i didn`t know i could just make a difference at different potencials. Nah, don`t bother with EE, i guess arcade life taught u very well. Thx for the patience and for teaching me.
      Ok, here i go waiting for parts coming from post office...hate this part.
      Besides, i should bother with 1/2 or 1/4 W heat dissipation?
      Dude, lol, I like your attitude :thumbup: , apologies if I came across like a bit snarky(somewhat like an a$$hole).

      But yeah, what exactly are trying to do? Why are you trying to add 3 leds? I think 1/2watt is fine for what you want to do, what size leds are you using? You will get better suggestions/help to your end goal.
      Multis: CPS2│CPS3│ST-V│F3│GNET│TTX2│NAOMI
      Superguns: Jasen's MK30ADCAP│RGB's HASv3
      MB: NAOMI 1,2│MV-1FZ & MV-4│IGS PGM│SEGA ST-V│TAITO F3│TTX2,X3
      CAPCOM CPS*│RINGWIDE/RINGEDGE 1, 2│HYPER 64
      LINDBERGH Y/B|IREM M*|CAVE (ALL YOUR BASE)

      +++
    • Assuming you want to wire multiple leds (3) from the same source as one circuit, you must consider if they will be wired in series, parallel, or a combo of both. Pros and cons to each wiring method, application specific.

      Whenever I design something with LEDs, I use cheat sheet online calculators to give me an estimate.

      LED series/parallel array wizard -- led.linear1.org/led.wiz

      Here is an example of series wiring, with your specs:


      You can also be brave and experiment, leds and resistors are cheap. You don't have to use the exact value from the calculator, try values higher or lower by 25% and see what you get :)
    • my goal is to use a saturn case for a supergun. I want to use the led like the original one( 2 small rectangulars) and i dunno maybe 1 or 2 more for doing some ``show``(high light leds), like when opening the disc tray or coming from something that i can draw, i dunno( i`m doing a mini-drill, hm, at least trying, but i`m missing parts). Right now, i just painted the case with maserrati blue.

      And i didn`t see that as being an asshole, i saw that as patience, really. But now... i can change the idea haha
    • TheBortot wrote:

      my goal is to use a saturn case for a supergun. I want to use the led like the original one( 2 small rectangulars) and i dunno maybe 1 or 2 more for doing some ``show``(high light leds), like when opening the disc tray or coming from something that i can draw, i dunno( i`m doing a mini-drill, hm, at least trying, but i`m missing parts). Right now, i just painted the case with maserrati blue.

      And i didn`t see that as being an asshole, i saw that as patience, really. But now... i can change the idea haha
      Cool, so you want to house the supergun inside a saturn case.

      I guess you have the supergun part installed/laid out inside the case?

      Do you want the led just for show, or to be useful in the sense of the system being turned on, another led when to be on when you open the cd tray, or you just want them to be on all the time?

      Show us some pics of what you working with.
      Multis: CPS2│CPS3│ST-V│F3│GNET│TTX2│NAOMI
      Superguns: Jasen's MK30ADCAP│RGB's HASv3
      MB: NAOMI 1,2│MV-1FZ & MV-4│IGS PGM│SEGA ST-V│TAITO F3│TTX2,X3
      CAPCOM CPS*│RINGWIDE/RINGEDGE 1, 2│HYPER 64
      LINDBERGH Y/B|IREM M*|CAVE (ALL YOUR BASE)

      +++
    • i`ll try that, @brizzo, thanks! Resistors are cheap indeed,but what really is expensive and is dificult is things coming from post office here. Not like the US. Maybe it`s good to me to control the anxiety...

      Another thing that is bothering me and i can`t think why is:
      at the power button in saturn, there is a KC222M capacitor like this:

      google.com.br/url?sa=i&rct=j&q…fW48&ust=1511400639168385

      Well, the button says 5A/40A 250v, so i can use it in arcade with no problem. But I should take this cap out or include it?
    • i was about to take pictures, but the varnish is still wet. Tomorrow i think that will be fine. I`m using a case of the Oval Buttons Saturn, so it would have a rectangular led power, an ``acess`` led, when i open the disc tray would be a high light or under acrilic part and maybe one more at the cartridge input, where the jamma goes out.
    • TheBortot wrote:

      Another thing that is bothering me and i can`t think why is:

      at the power button in saturn, there is a KC222M capacitor like this:

      google.com.br/url?sa=i&rct=j&q…fW48&ust=1511400639168385

      Well, the button says 5A/40A 250v, so i can use it in arcade with no problem. But I should take this cap out or include it?
      That's what is called a spark arrestor capacitor, it is used on AC voltage switches to prevent electrical arcing at the switch terminals/contacts. So you should leave it there if you are using it on the AC line to the power supply. If you want you can replace it with a new/fresh one of a similar rating/type.
      Multis: CPS2│CPS3│ST-V│F3│GNET│TTX2│NAOMI
      Superguns: Jasen's MK30ADCAP│RGB's HASv3
      MB: NAOMI 1,2│MV-1FZ & MV-4│IGS PGM│SEGA ST-V│TAITO F3│TTX2,X3
      CAPCOM CPS*│RINGWIDE/RINGEDGE 1, 2│HYPER 64
      LINDBERGH Y/B|IREM M*|CAVE (ALL YOUR BASE)

      +++
    • well, i just tested the button plugging both wires to the 2 ``AC`` of the PSU. Lol, all of the electrodevices that were in the same place went down. I thought i lost the psu, but no. What i did wrong?

      before that, i checked were it was plugged in the saturn and matched with analogy for the psu.
    • TheBortot wrote:

      well, i just tested the button plugging both wires to the 2 ``AC`` of the PSU. Lol, all of the electrodevices that were in the same place went down. I thought i lost the psu, but no. What i did wrong?

      before that, i checked were it was plugged in the saturn and matched with analogy for the psu.
      You better post some pics of what you are doing before you power anything up, before you electrocute yourself or set your house on fire, lol. It sounds to me that you plugged the switch straight into your AC line and blew a fuse or tripped a breaker in you panel.
      Multis: CPS2│CPS3│ST-V│F3│GNET│TTX2│NAOMI
      Superguns: Jasen's MK30ADCAP│RGB's HASv3
      MB: NAOMI 1,2│MV-1FZ & MV-4│IGS PGM│SEGA ST-V│TAITO F3│TTX2,X3
      CAPCOM CPS*│RINGWIDE/RINGEDGE 1, 2│HYPER 64
      LINDBERGH Y/B|IREM M*|CAVE (ALL YOUR BASE)

      +++