Hello everyone,
I would like to know if I can power my arduino mega through the USB port with a 2 amperes supply from an external battery power, as described in this picture : https://photos.app.goo.gl/grTTSqPPB5QdaSBM9
I know that there is a current limit on the USB ports of 500mA, so 2 Amperes is 4 times bigger than what is advised.
Will it harm my arduino card ?
Thank you
The Arduino won't be pullng anything like 2A. The supply doesn't set the current, it sets the voltage.
short answer - YES. its ok
Worth having a look at ohms law
Look at it this way;
If you had a kids wagon that could carry 200 lbs. But you only put 50 lbs in the wagon. The wagon would then only be carrying 50 lbs. Even though it COULD carry 200 lbs
For voltage devices (i.e. devices meant to run on a specific voltage like the Arduino) The Arduino board will only draw about 0.1 amp, even though your power supply COULD supply 2 amps.
Or another analogy: If you had an automotive battery capable of 400 amps and you connected it to the 12V input of the Arduino. The Arduino would still only use 0.1 amps of the 400 available.
CAUTION: While most devices are meant to run on a specific voltage there are exceptions. One being an LED.
Simpler analogy: is your 50W light bulb at all troubled being plugged into your local multi megawatt power station?
AWOL:
Simpler analogy: is your 50W light bulb at all troubled being plugged into your local multi megawatt power station?
Well yes, the voltage at the power station is many kilovolts!! A better way to put this is that a phone charger
will run from a wall outlet rated for 13A or whatever, it just wants the right voltage and enough current
capability.
Thank you everyone for your responses, the one of JohnRob was particularly clear. So I won't be afraid anymore by plugging my 2 A battery to my Arduino card. Thanks !