AC power to LEDs

insanepanther

Hi there,

I am going to br running 9 of the candle flicker LEDs in parallel using AC power via a household outlet. I know I am going to need to use a transformer but I am not sure what voltage I need. Also, do I need resistors on each of the LEDs? Iam using 9 of the following LEDs

Specifications

Color: Yellow
Peak Wavelength: 590 nm
Package: Round 3 mm
Lens type: Milky-white
Viewing angle: 50 degrees
Intensity: 900 mCd typ. at 20 mA
DC forward current: 30 mA
Forward voltage (typical): 2.1 V
Lead-free (RoHS compliant)
Manufacturer: Betlux Electronics
Manufacturer part number: BL-L314UYW-B-S3

Thanks

Lenore Edman

First, do not hook them directly to AC! You will need to use an AC to DC converter. It is most efficient to start with a low voltage, something like 3 V if you can find it, but likely 4.5 V or 5 V will be easier to find. Yes, you will need to use current limiting resistors for each of the LEDs. You can read about how to determine the resistor value here:

http://www.evilmadscientist.com/2012/resistors-for-leds/