In another post it was verified that a USB adapter would be safe to plug into the 5v rail, which got me to thinking about wall wart style power supplies.
I have a whole bunch of old Motorola/LG 5v supplies with a proprietary connector for old basic phones. They are typically rated 4.75-5v & 300-500mA.
Do these count as "regulated" power safe for hooking up directly to the 5v rail, assuming I check actual voltage first and stay within current limits?
Yes, fine on the 5V rail, and you may wish to learn about what current is because whatever you mean by "stay within current limits" is an indication that you do not understand it.
Regarding current limits, perhaps I should say maximum rated current.
I'm assuming you are referring to the fact that the supplies will deliver more than the number says, with risk of fire, so technically it's not a limit. If there's something else I'm missing here let me know and I can google it. But, I think it's just a case of using the wrong term.
Thanks for the reply.
keith204:
Regarding current limits, perhaps I should say maximum rated current.I'm assuming you are referring to the fact that the supplies will deliver more than the number says, with risk of fire, so technically it's not a limit. If there's something else I'm missing here let me know and I can google it. But, I think it's just a case of using the wrong term.
Thanks for the reply.
Confirms what misinformation I sensed. Current isn't pushed out from the supplies. There is no 'limit'. You could plug a 5V 10000mA supply into your Arduino and magically it would be just fine. If the 'why this works like this' boggles you, then do please do some google learning. In short, devices pull what current they need. They don't get force fed current until they explode.
I'm not sure what terminology to use, but what you said is exactly what I understand. This is why plugging a 12V LED strip that consumes 5A into a 2A supply will be just as bright, but the supply will be very hot and risk fire.
Please advise on proper terminology I ought to use.
Ah I see what I said that was confusing. "Will deliver more than what the number says" is referring to the number on the supply. A 800mA supply will deliver more than 800mA if the components draw it. Or less if the components draw less.
But I do feel it was completely appropriate for you to call me out on this, because when dealing with electricity, it's better to be safe.
I think you've got it right Keith. If you have an Arduino Uno, the most it should draw is 200mA, so if your supply provides 300mA, you should be fine. Pretty close though. Be sure to use a separate supply if you do any heavy lifting with your Arduino.