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Topic: Power supply for Arduino (Read 511 times) previous topic - next topic

yerzhik

I am not sure if this is the correct forum branch to ask such question, so I am sorry if I am asking in a wrong place.
I want to supply the power to my arduino uno through the USB cable (used to connect to the PC) by connecting the other part to the USB battery,
the USB battery is providing this parameters:
DC 5V - 1000mA.
I am afraid that I can't do it, only if 500mA, right?

James C4S

Current ratings are a capacity rating.  Electronics only draw the amount of current they need.  So if you have a 1000mA source and your electronics (such as the Arduino) only draws 50mA, it will still only draw 50mA.

The challenge here is that when powered through the USB port of the Arduino, there is an on board fuse that limits current to 500mA.  So even if your source is 1000mA capable, the Arduino will not allow drawing full capacity.

The alternative is to hook the battery directly to the 5V node, which bypasses the on-board fuse.
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yerzhik


Current ratings are a capacity rating.  Electronics only draw the amount of current they need.  So if you have a 1000mA source and your electronics (such as the Arduino) only draws 50mA, it will still only draw 50mA.

The challenge here is that when powered through the USB port of the Arduino, there is an on board fuse that limits current to 500mA.  So even if your source is 1000mA capable, the Arduino will not allow drawing full capacity.

The alternative is to hook the battery directly to the 5V node, which bypasses the on-board fuse.

Thank you for the answer. Now I am safe to use it :)

gunric

There is a quite common misunderstanding of voltage and current. Quite many think a car battery is dangerous while there actually is no risk at all to grab the + and - poles of it. But if you try to shortcut the same battery with your wedding ring, you will see smoke coming from your ring finger in a second or so. All is about resistance where the body has high resistance which gives no current with 12 volts and the ring has very low resistance which the car battery supports with an enormous current.

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