Some notes that could be useful when dealing with Arduino boards.
- What is the voltage range when powered from the jack?
- 6..20V - if supplied with less than 7V the 5v might become
lower thus board becomes unstable.
- What aperage can the internal power supply give?
- When powered from USB it is 500mA, when it is using power supply
it can present max 1A
- What is the power consumption of an Arduino being powered from a 9V