Newbie question here. I'm Having this schema. I have a circuit to switch 8v power using a MOSFET and an NPN transistor with Arduino 3.3v The power of the switched side will be around 2A (if this matters somehow).
I have 2 questions.
What's the value of R55 , how is it calculated and is it related to the 2A in any way ?
When the Arduino pin is in LOW state, point D measures 8V. When the Arduino pin is in HIGH state, point D measures around 0.3v. According to my understanding point B is always on 8v because it get's voltage from the battery in point C. How come that the transistor "breaks" that from point D to B and lowers/overrides that voltage coming from point C ? I hope I got my question right here:)
Thanks!