Hello.

I was making some tests with an IRF640, just for tests and "empirical" learning...
The idea is to an AT89S52 drive it to make a RGB PWM controller later.
Some people told me about about gate current and I became curious.

In this tests I'm using 4 LED bars which draws 1.32A (all together) directly connected to the supply, It have the current limiting resistors on itself and it is 12v (common anode), as I seen the LEDs are organized in paralel but in series of 3 LEDs in the bar.
I put a amperimeter in measuring the bar current and another measuring the IRF gate current (set to 200uA scale).

Gate open (NC), bar current is 1.15A, gate current 0uA
Gate connected to ground, bar is off, 0A, gate current 0uA
Gate connected to 5v, bar current is 1.11A, gate current 0uA
Gate connected to 12v, bar current is 1.15A, gate current 0uA

So, I got there is no current in the gate, am I doing this right?

Also, as I seen there is no current in gate I made another test, put a potentiometer as voltage divisor and the swipper/cursor connected to IRF's gate, and could control the brigthness of the light bar, the IRF got a bit hot this time, but I think the raise in temperature is normal, but dont know if is right to put a potentiometer in the IRF's gate.

So, if no current in gate, I tought in using a ULN2803 with 12v pull-ups then connected to IRF gates, could this work?

Sorry for the dumbness.

Thank you very much.