I have an arduino UNO R3 and a RGB strip. I want to controle the RGBs but they have 3 GND and 1 5V+. I am going to use transistors but i want to program my RGBs, so they can fade from blue to white. I for that I'm gona need to output 0.5 A, 0,6 A and 0,7 A to make dade effect (This output si going in to transistors) . As I was researching the arduino outputs 0,2 A (200mA). How do I program my arduino to do that?
Thanks if you rade all this. I will be happy if someone can help me.
That's what your transistors (or MOSFETs) are for. To "boost" the voltage and/or current. It just takes a small current (or no current into a MOSFET) to control the main-current through the transistor/MOSFET and the load (the LED).
Here is a MOSFET driver circuit. Of course, you'd need 3 of them. It's shown driving a motor with a 12V supply but it can also be used with a 5V and a 5V LED strip. Since you don't have an inductive load you can leave out the diode.
A regular bipolar transistor can be used in a similar (but not identical) circuit.
Dimming is normally done with PWM (see the Fade Example). PWM pulses on & off faster than your eye can see which makes the LED appear to dim (and it's off part-time the average voltage & current is reduced).
The driver circuit will "pass-through" the PWM and it will work just like a regular little LED without the driver.