I am pretty much a complete beginner (or almost) when it comes to electronics and the arduino in particular, so if you have a question , your best bet would be to ask on the official forums.
Here are a few things i discovered while tinkering though, hope you find it usefull!
1- Q: Arduino seems great, where can i find more info about it ?
A: Take a look at www.arduino.cc
2-Q: I just fried my Tip120 Transistor while trying to use a 12v pump : what happened?
A:The transistor most probably could not handle the amperage : always check the actual resistance of your pump/motor and do the according calculations :
- Measure the resistance of your pump with a multimeter
- U=R*I (U: v, R: ohm, I:A) so if you have R, you can do inputVoltage/R=Actual Amperage
- For example i measured a value of R of about 2.2 Ohms on the pump i had
- With a 12v power supply : 12/2.2=5.4545 so a bit above the normal A of the Tip120 (rate at 5A continuous , 8A peak ) so no wonder it was getting hot!
If i made any mistake, just drop me a line and i will correct it.