My Getting Started With Arduino book arrived yesterday, and I'm hoping my Arduino beginners kit will arrive today - I'm very excited!
However, after reading the book last night, I find I don't understand the electronics aspect - the programming I'm fine with. I have a few questions to pose regarding circuits in the book - I hope I'm not breaking forum etiquette by posing them all in one post, but here I go...
Page 43 Figure 4-6 The circuit shows a wire coming out of 5V and into a push button. There are then two wires coming out of the push button, one going directly to pin 7 and the other going to Ground via a 10K resistor.
Why two wires, and why the resistor? Why not just one wire to pin 7?
Page 58 Figure 5-4 The circuit shows a wire coming out of pin 9 (which I assume will provide power on a digitalWrite?) into an LED. There is then a wire coming out of the LED to Ground via a resistor.
Again, why the resistor? Previous examples show an LED connected to pin 13 and Gnd without a resistor - why does this one need a resistor? What purpose does it serve?
Page 71 Figure 5-7 The circuit shows a wire coming from 9V to the middle pin on a MOSFET transistor (the collector I assume?) via two routes - one via the motor on a fan, and the other via a resistor. There's then a wire from pin 9 to the transistor (base?) and a wire from the final pin (emitter?) to the Gnd.
I get the feeling the answers to the first two questions will answer this one for me: Why the two routes from 9V to the resistor?
In my limited knowledge of electronics, I understand a simple circuit: electricity flows from one terminal of a battery through a few components and back to the other terminal. I can't understand how the Arduino board provides 3V, 5V and 9V pins, yet they all go back to the same Gnd pin.
If I were to connect a 9v battery to a motor and to the collector and emitter of a transistor, would I be able to use a pin on the Arduino to switch the transistor on and off? What would I connect to Gnd?
Finally, can you recommend a good site for beginners electronics that I can read articles covering all these things?
Thanks, A VERY excited Arduino convert!