I am controlling a 5m RGB LED strip with 300 5050 SMD LEDs. The schematic I use is the same as here: RGB LED strip tutorial. The only difference is that I'm using three IRFZ44N transistors and a power adapter with output of 12V and 1.25A, although for full brightness the current input should be 6A since each three-color LED requires 20mA.
This setup works fine, I can't really imagine the LEDs being any brighter. The problem is that certain chips on Arduino get really hot after a few minutes. The hot chips are marked on this photo: http://db.tt/Gv6xfz2K, the most hot is number 2. I am wondering what are the functions of these chips and how change my RGB LED controller to work without heating up.
Chip 2 is the seriese diode on the power input jack. This is rated at only 1Amp. Chip 1 is the voltage regulator.
It looks like you are drawing too much current from the +5V line of the arduino and you need an external regulator.
You are using the Vin line. That current passes through that diode that is getting hot. Rewire your circuit so that you get the 12V direct from the wall wart and not through that diode.
your gray wire is the problem, connect this to the 12V adapter. Then the strip is powered by your adapter
and not bythe arduino. The LED's will even be brighter ..
But to limit the first current into the gate use 1 kOhm in serial to your digital output pin..