Supplying arduino UNO with 5 volts

Other Hardware General Electronics
1

I have an AC to DV adapter that supplies 5volts and a maximum current of 1000mA with a positive polarity

is it okay to plug it in the Arduino Uno Power Jack ??

2

No. The power jack feeds the on-board 5V regulator which needs about 7V to produce 5V.

I think your Arduino might work on whatever voltage gets trough the regulator but it won't be running on 5V

You can connect 5V to the +5V and Gnd pins. There is a slight chance this might damage the 5V regulator but the risk is low.

3

johnwasser:
No. The power jack feeds the on-board 5V regulator which needs about 7V to produce 5V.
...

Agree,

NCP1117ST50T3G works at 5 V need Vin >= 6.5V and D1 has 0.5V voltage drop, total is 7.0V.

4

If it's a regulated supply (measure it with no load, see if it's outputting 5V) then you can connect it to the Arduino Vin pin.

5

You should test it out with a voltmeter/multimeter first, but I've done it with successful results before.

-Mr_E

6

fungus:
If it's a regulated (5V) supply (measure it with no load, see if it's outputting 5V) then you can connect it to the Arduino Vin pin.

Not the Vin pin, the +5V pin.

7

johnwasser:

fungus:
If it's a regulated (5V) supply (measure it with no load, see if it's outputting 5V) then you can connect it to the Arduino Vin pin.

Not the Vin pin, the +5V pin.

true. the vin pin feeds directly to the barrel jack. if you snip the wires and stick the positive into the 5v pin it will work.(be 100% sure that is is a more or less stable supply of 5v exactly.)

8

You should not connect a supply to the 5V pin and use USB at the same time, however.

9

And to further cloud the issue the arduino product page for the Uno says you should not supply external +5vdc to the shield 5V pin, but without further official explanation:

5V.This pin outputs a regulated 5V from the regulator on the board. The board can be supplied with power either from the DC power jack (7 - 12V), the USB connector (5V), or the VIN pin of the board (7-12V). Supplying voltage via the 5V or 3.3V pins bypasses the regulator, and can damage your board. We don't advise it.

Lefty

10

There are three types USB cables;-

  • data-only USB cable ( no 5 v)
  • USB Charging Cable (no data)
  • Standard USB cable

Use USB Charging Cable supplying arduino UNO with 5 volts power.