I am trying to power 4 led's as if they are part of an RGB light strip. I am powering them off 12v, as the end goal is to add more and create my own version of a custom light strip. I am using common anode led's and using the Arduinos PWM pins.
My question is about the use of resistors that are found in RGB strips. With all Led's in parallel, will I need to use them? I haven't hooked the board board up yet out of fear of blowing the LED's, I spent $7NZD on each led, so want to check. Will the 10k resistors on the MOSFETS be enough?
The only information that I can find on these are as follows:
Specifications Size (mm) 5 Superflux 5 Superflux 5 Superflux Colour Red Green Blue Lens Waterclear Waterclear Waterclear Viewing Angle (Degrees) 60 60 60 Wavelength (nm) 643 528 468 IF Typical (mA) 20 20 20 VF Typical (V) 1.8 3.2 3.2 IV Typical (mcd) 200 900 150 IF Max Continuous (mA) 20 20 20 Preferred Value Series Resistor 5VDC 160 91 91 9VDC 360 300 300 12VDC 510 470 470
Common Anode
Pre-cheers and thanks for any help.
DanielDoesDesign.
12volt LED strips have three of the same colour LEDs and a resistor in a string.
You can't do the same with LEDs that have the three colours connected to a common pin.
"I spent $7NZD on each led"
Wow. That's seriously overpriced.
You can get addressable LEDs like that (not on a strip) locally for <NZ$0.50
They don't need the mosfet, but must run on 5volt.
Search for "addressable LED" on TradeMe.
You normally have 220ohm between Arduino pin and the gate of a fet (must be logic level).
And a 10k bleed resistor from each Arduino pin to ground.
In your diagram, each cathode of each LED needs a current limiting resistor.
A 12volt supply is "wasting" about 75% in the resistor as heat, since Vf of the LEDs is ~2.2-3.3volt.
Better use a 5volt supply (old cellphone charger).
Leo.. (NZ)
The reason I am using 12v is that my project is for powering a lot more than what I have at the moment. I am creating LED lit lettering, and each letter will be about 4 led's in series (I have just decided).
I have found some better diagrams of what I want to achieve. However there are two diffrent versions.
This version has a resistor at the end of each series chain,
the problem i am now facing is that I am not sure how to determine what makes connecting these led's in this fashion "in series", to me it seems that no matter what you do, the result is always going to be parallel. Can anyone explain this?
Just because they are in two row's of two, for me, doesn't make them a 2 x series connected led's and then 2 parallels. To me it looks like the entire thing is in parallel, and that there is no way to escape this. If i am wrong can someone explain it to me?
When an led has 6 pins, then I can understand how to achieve series, but with 4 pins, I am lost.
