questions for simple PWM circuit

I know this is an old topic. I would like to use this circuit as an LED array dimmer but I have a few questions.


12V input
LEDs- 3.6V, 30mA (typical) - 3 parallel branches with 3 series LEDs

R1 = 500k 500mW 20%
R2 = 6k 3W 5% (?)
Rload = (is this where the LEDs are inserted ?)
C1 = 3.9nF 50V 10%
Rlimit = 40 3W 5%

(a current limiting resistor for the LED branches. Can all three branches share a resistor or is it best to have 3 separate resistors?)
​

Q1 = part number IRFI540NPB (correct one?)
D1 & D2 = 1N914

What are points A and B in the schematics provided by SGT Wookie?

If I double the number of LEDs 6 parallel branches will any component values change.

Thanks,
Travis

 

All resistors can be 0.4W or whatever you have handy.
You need a resistor for each LED.
The diodes are fine.
Pretty much any N-channel MOSFET is OK.
A and B are the traces on the oscilloscope.
The same components should be fine for 6 LEDs.
Rload is where the LEDs and limit resistors go.