I want to control the brightness of a 12v light and so I am using transistors in the high side of the bulb
(NPN and then P-Mosfet) to control the light, and an Arduino pin to control the NPN. Actually, all I want to do here is run the bulb at a single reduced brightness when commanded by the Arduino. At other times it will be illuminated at full brightness.
Can I use PWM on the Arduino to the NPN base pin to get the transistors to turn on and off according to the PWM waveform? Or will the NPN just see the PWM wave as a reduced voltage signal and turn solidly ON if the voltage is high enough or solidly OFF if not? I will be sure to choose transistors that can switch at the speed of the PWM waveform.
If I'm on the wrong track, what do I need to investigate to change this design?
Thanks in advance