Can I simultaneously power the arduino uno with an ac/dc adapter and having it connected to the usb cord? I'm testing some servos and I don't think the current from the usb port will be enough to power 4 servos at the same time, sorry for the stupid question but I'm new with arduino.
maad:
Can I simultaneously power the arduino uno with an ac/dc adapter and having it connected to the usb cord? I'm testing some servos and I don't think the current from the usb port will be enough to power 4 servos at the same time, sorry for the stupid question but I'm new with arduino.
Yes you can. The board is designed that if both USB power and external DC power is available it will utilize the external DC power and isolate the +5vdc from the USB port.
However maximum current available to use when using the external DC power is not all that much more then from USB, and certainly not enough to support 4 servos at the same time. Your servos should be powered from and independent +5vdc power source, with at least 1 amp of capacity per servo being used, so 4-5amp supply would not be overkill. Be sure to connect the ground from this external servo power supply to a arduino ground pin.
Lefty
So, if I power the servos from the +5v and Gnd pins it also provides power for the logic circuit? and it won't be necessary to power the board from the jack? am I right?
I think you got that backwards. The USB in will not give you enough current to drive 4 servos. Or if it does, it will be unreliable. Or is that not what you meant?
In your first reply you recommend me to power the 4 servos from and independent +5v power source ( where should i connect the external power source?) at the jack or at the pins (+5v and gnd)?
Woah... back up a bit....
In your first reply..
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That was two different members there, but what they mean is, power the servos from a power supply which is not through the Arduino.
My pic below shows the idea:
- Power the Arduino however that's convenient for you, eg 5V in the USB or 7+V in the barrel
- Power the servos from their own supply, usually 4.8 to 6V but check the servo datasheet
- Control the servos from the Arduino
- Link the grounds