if you use a FET you can put a resistor in series with the source to ground,
amd the 5v gate drive coming from the microcontroller will be lessened by the
resistor voltage drop.  we can look at it tomorrow night if you want.

On Mon, 25 Feb 2019, robb wrote:

> anybody haz a circuit diagram that limits current through a transistor by
> means of adjusting the duty cycle of a microcontrolloer (arduino/esp8266)?
>
> seems like all the diagrams i can find use a current sense resistor & not
> the mcu
>
> thx4haxing
>