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Topic: Powering a Uno (Read 1 time) previous topic - next topic

Mole

Hi,

I have a maplin USB power adaptor (Code: N69CX).  Is it OK to power my Arduino with this?

On the packet if says the Voltage is 5V and the Current is 1.0A.

Thanks

majenko

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MarkT

USB power is required to be regulated 5V and usually can be relied upon to provide at least 0.5A, so such USB power adapters are fine power sources for 5V digital circuitry.
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CrossRoads

#3
Sep 20, 2012, 08:08 pm Last Edit: Sep 20, 2012, 08:11 pm by CrossRoads Reason: 1
If you have a recent Uno, be sure to connect to the USB connector.
Connecting to the barrel jack and/or Vin, 5V is not enough to power the regulator.
Connecting to 5V may damage the Uno's 5V regulator unless you add a diode from 5V to Vin (i.e. across the regulator) - see the LM1117 datasheet for a better description.
http://www.ti.com/lit/ds/symlink/lm1117-n.pdf
Page 12-13, para. 4.0
Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

Mole

Thanks everyone.

Just to confirm - I am using it to connect to the Arduino's USB port.

I just wanted to make sure that 1 amp wasn't going to do any damage.  I've only been able to find out that a PC USB port outputs up to 0.5 amps to the Arduino, so wanted to check that doubling it wouldn't be too much for it.

majenko

1 amp is what it can provide, not what it willprovide.

The voltage is the fixed value, not the current.
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CrossRoads

Yes, I think its a shame they changed the regulator and didn't make it safe to power from the 5V header.
Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

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