Hi. I have several LEDs with 300mA each. I use an additional power supply to run the LEDs so that the Arduino is not damaged. But I also want the possibility to dim the LEDs. Is it a good idea to do this with a MOSFET and if so, can it damage an LED to dim it?
Thanks for your help
Normally this type of led requires a constant-current (CC) power supply circuit, otherwise the LED will be damaged. Most CC circuits cannot be dimmed by a MOSFET on either the input or output of the power supply. You need a CC circuit that is designed to be dimmed, one that has a PWM input. With this type of supply, you will probably not need a MOSFET because the PWM input can be connected directly to an Arduino PWM output (but check the specs of the CC circuit).
I have changed the LEDs a little. Now I use "G4 LED dimmable 2 W 36 x SMD 12 V AC / DC" LEDs. (Amazon: link) Should I use a MOSFET or a PWM to control the LED?
Thanks for your help.
It may work with the MOSFET, not sure.
We cannot tell from that link. We would need to know details of the circuit built-in to the led module.
However, the page says "special feature: dimmable" so there is a good chance that using a MOSFET and PWM signal from the Arduino could work. Follow @jim-p 's circuit from post #2, but you can omit R3.
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