| Electronics > Beginners |
| Is it safe to power an Arduino project with a phone charger plugged to wall? |
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| engineheat:
Those phone chargers that outputs 5V DC via a USB cable, I plan to cut the USB cable wire and power the 5V input of the Arduino Pro Mini with the wires. Is this safe? I need a reliable power supply (no batteries), but I heard it's dangerous to power off the 120V AC for something like this. |
| ebastler:
You are relying on the phone charger to keep you electrically isolated from the mains voltage. So don't use a no-name Chinese charger (or a pirated copy claiming to be Apple product or whatever -- not always easy to spot). If you use a known-good brand name charger, you should be safe. The other danger is that you might harm your Arduino board or homebrew electronics when experimenting. Proper lab power supplies have an adjustable current limit, so if you accidentally create a short circuit on your Arduino board, the power supply will only provide a limited amount of current. The phone charger will provide all the current it can; typically 1 or 2 Ampere. That won't start a fire, but may damage electronic components. Given the cost of an Arduino, I would take that risk. |
| engineheat:
What about a battery bank that outputs 5VDC to charge devices? Do those give max current too? (usually 1 or 2A) |
| bd139:
I have a bunch of Nokia AC11 chargers floating around for this stuff. They’re not too electrically noisy, dirt cheap and aren’t made of poo. Battery banks I’d skip because not all of them have a current limit that works. They can shift quite a bit of energy very quickly. |
| sokoloff:
--- Quote from: engineheat on March 30, 2019, 11:56:22 am ---What about a battery bank that outputs 5VDC to charge devices? Do those give max current too? (usually 1 or 2A) --- End quote --- They have a max rated current, which is nowhere near the same thing as a current limit as you'd find in a typical bench supply. IOW, if you add a load to it, it only promises to deliver at least the rated current without excessive voltage drop. It does not promise to not deliver more... |
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