power supply

Hello. i am using Arduino mega 2560 and i have some questions:

1) if i connect both the usb cable to the arduino and the power supply to the arduino, which supply voltage the Arduino will choose?

2) the usb supply 5V and in the data sheet says that that less than 7v is not good, so i have to use power supply of 7-12v?

3) what is the difference if i plug power supply of 9 or 11? and what is the exact supply voltage recommended?

thank you,

Hello. i am using Arduino mega 2560 and i have some questions:

1) if i connect both the usb cable to the arduino and the power supply to the arduino, which supply voltage the Arduino will choose?

2) the usb supply 5V and in the data sheet says that that less than 7v is not good, so i have to use power supply of 7-12v?

3) what is the difference if i plug power supply of 9 or 11? and what is the exact supply voltage recommended?

thank you,

1) If the power supply connector is fed with at least 7 V the usb power is not used. 2) The 7-12 V power is regulated down to 5 V on the board. 3) The only difference is that the higher the power supply voltage the hotter the on-board regulator gets. It is fine anywhere between 7 and 12 V unless you are powering something that draws a lot of current from the Arduino.

Russell.

Note: "a lot" means more than about 100 mA.

so which power supply are you suggest? usb or 7-12?

thanks,

Whichever is most convenient for you.

Russell.

its doesnt affect the arduino voltages and currents on the pins?

and another question. the digital i/o pins and pwm pins and analog pins, which current they provide max and min?

thank you,

USB supplies 5v straight into the ICs. Vin goes into a regulator. This means 5v comes from the regulator if 7 v or more is fed into the Vin.

The problem of putting more than say 9v into the Vin is that the regulator has to dissipate the extra voltage as heat. The heat depends on the current drawn so 9v at 300mA is ok but 20v at 300mA will be far too high.

7v to 12v is the recommendation.

Weedpharma

Crosspost.

See here

@maor444, do not cross-post. Threads merged.