Hi i was wondering if i could hook up a 120v transistor (don't know if i should use pnp or npn) to my home lights and pmw it with my arduino. Eventually i want to be able to do this remotely, possibly by an ethernet shield.
You said what I meant in a far better, kinder and more concise manner. I love LMR-so many people I can respect and learn from here.
Please don't experiment with this until you've had a great deal more experience with electricty and electronics. I can't stress this enough.
The least damage you'll do is to fry your Arduino, but I'm afraid if you experiment with this you'll start a fire or electrocute yourself. The main problem here is that the Arduino runs on DC and your home lights (mains) run on AC. There is also the difference in voltage secondary to that problem (Arduino system is 5v and mains is 120v) and more over, I'm not quite certain you understand what's going on with your Arduino if you are going to "PWM it" through a "120v transistor." First I don't think you could find a 120v AC transistor with a 5v DC Base trigger voltage, but second, a transistor is mostly useful for digital switching-a PWM signal is meant to emulate analog level shifting and through a single transistor isn't much good. If you want to use an Arduino for home automation, it is possible, but I would recommend looking for a ready-made AC capable switching solution. *PLEASE* Do not try this yourself, at least not until every reason I've given for you not to here is obvious in retrospect.
Thank you for the heads up..I may just do this with a small led...