umm.. The questions came up while working.. First, look at this site that is simmilar with my project. https://arduino.stackexchange.com/questions/21016/how-to-connect-a-12v-power-supply-to-an-rgb-led-strip-receiving-rgb-values-via-a

Just say power supply is 3A 3V and using pwm, upper one is 255 and the others are 0, does red led take 3A3V or 1A 1V? In my project, it was 1A1V but I don't know why. Does the 0 mosefts are not blocking current? Is it flow to ground?

And I want to using both technology (like relay one and other).. Could you give me some help please :(

That's a link to a LED strip. A LED strip has LEDs, and also resistors to limit LED current.

The mosfet is just a switch, like a relay contact. Turning the strip on, or off, or on/off very fast (PWM). Switching a LED on/off faster than the eye can see is percieved as a dimmer light.

So why the question about a 3volt/3Amp power supply. To drive single power LEDs? You can't just power a LED with a 3volt (constant voltage) supply. Something else is needed to control/limit the current. Leo..

ohâ€¦ 3A3V was just an example.and LED also. My project is using motors.
My question is focused on pwm that all 0 or all 255(255 is all on state.)
If there is a 3 number of parallel circuit and 3 amperemeter, one mosfet is 255 and others are 0 state.
Then the state of ampere is my curious thing.

Not sure what you're asking, but with the LED strip it's three individual circuits. They have nothing to do with each other, apart from a common 12volt supply. Leo..

Can you post a wiring diagram along with that narrative? Very confusing.

A load has a response curve - for each value of applied voltage it takes a particular current. This response is a property of the load only.

If several loads are supplied from the same (voltage) supply they act independently as each has its own response, the presence/absence of other loads is not visible (assuming the supply can maintain the voltage properly).