Powering the arduino uno or Mega

Hi,

I just want to make sure my idea is safe before processing!

Is it possible to plug a stable, regulated, 5V DC source in the 5V header on the arduino to power it??

Thanks

Hi,

which 5V are you talking about? if you are referring to the 5V that is labelled on the board. if I am not wrong, those are actually 5V out.

What people usually do is to power the their arduino using USB or through an ac-dc power adapter (3.5mm) type?

johnyboy:
Hi,

I just want to make sure my idea is safe before processing!

Is it possible to plug a stable, regulated, 5V DC source in the 5V header on the arduino to power it??

Thanks

Yes, people do it all the time. However it is not without technical issues, as when you also then plug the arduino's USB cable you end up where both the PC's USB +5vdc is 'wired' to your external regulated +5vdc. This is not a good practice, to have two different voltage sources wired together without some form of isolation, but again many do it without problems reported.

Lefty

Hi,

Do you mean pumping 5V through the Vin? or the pin that is actually labelled 5V?

jerettk:
Hi,

which 5V are you talking about? if you are referring to the 5V that is labelled on the board. if I am not wrong, those are actually 5V out.

The shield 5V pin is actually wired directly to the boards +5vdc Vcc bus. So while the arduino designed it to provide +5vdc output voltage to power external components, it's quite possible to power the board by wiring a regulated +5vdc to this pin and ground, and many people do and have. There is the issue I raised below, but again it's not something that isn't done successfully by many in their projects.
Lefty

What people usually do is to power the their arduino using USB or through an ac-dc power adapter (3.5mm) type?

Power
The Arduino Uno can be powered via the USB connection or with an external power supply. The power source is selected automatically.
External (non-USB) power can come either from an AC-to-DC adapter (wall-wart) or battery. The adapter can be connected by plugging a 2.1mm center-positive plug into the board's power jack. Leads from a battery can be inserted in the Gnd and Vin pin headers of the POWER connector.
The board can operate on an external supply of 6 to 20 volts. If supplied with less than 7V, however, the 5V pin may supply less than five volts and the board may be unstable. If using more than 12V, the voltage regulator may overheat and damage the board. The recommended range is 7 to 12 volts.
Source: http://www.arduino.cc/en/Main/arduinoBoardUno