Can 12v LEDs be powered by 5v connection?

[Luigi87]

So apologies for my lack of electrical know-how, but I was wondering. I'm building an arcade controller that is USB powered, which I know is limited to 5v (it is to be usable on game consoles). The board I'm using has a setup for a 5v (VDD_5v I guess) setup to allow hooking up LED. Unfortunately I only have 12v LEDs (with integrated resistors) at the moment.


This is where my ignorance comes into play. I was wondering if I would be able to still hook these LEDs up in parallel to get some illumination out of them (reduced naturally), or if they wouldn't even light up (or worse potentially damage my PCB?)

[PL1]

Welcome aboard, Luigi87.   

Yes, you can use a 5v power supply to run 12v LEDs.  It is the best choice for your proposed setup.   

1.  The electrical difference between 12v and 5v LEDs is the current limiting resistor value.

2. The 12v LEDs won't draw as much current with the higher value resistor.
(Paradise Arcade 12v LEDs powered by 5v only draw 5.83 mA each vs ~20 mA powered by 12v)

3.. They won't be quite as bright when powered by 5v, but they are still plenty bright IMHO.
(Wiring them in parallel won't reduce the brightness)

The big advantage to using 12v LEDs powered by 5v is the reduced current draw, especially if you ever plug into an un-powered USB hub. (USB spec is supposed to limit unpowered hubs to 100mA per port)

Just wire the LEDs in parallel like this using a 0.250" Quick-Disconnect daisy-chain.



If the LED doesn't light unplug/turn the LED 180 degrees.


Scott

[Luigi87]

Thank you very much! That is a big help (and a massive load off my mind).
And thank you for instructing which quick connects I need. I have to head to my local electronic components story tomorrow to pick some up, as I only have .110 and .187 on hand, and I wasn't sure the size the lamp/microswitch holders needed (as I did see they were noticably larger).

[PL1]

Glad to assist.   

LMK if you have any further questions.


Scott

[RandyT]

The big advantage to using 12v LEDs powered by 5v is the reduced current draw, especially if you ever plug into an un-powered USB hub. (USB spec is supposed to limit unpowered hubs to 100mA per port)

Another big advantage is that the inexpensive LED's supplied with these types of buttons aren't being driven nearly as hard at 5v.  They are probably being run a bit "hot" with the standard resistor at 12v, to get the most light out of them, at the cost of longevity.  If 5v makes them bright enough for your tastes, then you can expect them to last a lot longer at that voltage.