Are there any reasons why a DC power jack/connector (for Wall adapter) is provided on the Arduino boards?
I'm curious because it appears to me that, for almost all situations, it wouldn't have any advantage (in sourced current, or in convenience) that isn't already provided by either a USB cable from a computer or else a USB wall charger cable.
giantsfan3:
Are there any reasons why a DC power jack/connector (for Wall adapter) is provided on the Arduino boards?
It appears to me that it wouldn't have any advantage (in sourced current, or in convenience) that isn't already provided by either a USB cable from a computer or else a USB wall charger cable.
Ummm... so you can use a variety of power sources,
eg. Batteries.
Or power supplies with other voltages then 5V (the jack has a voltage regulator).
Or...
giantsfan3:
Are there any reasons why a DC power jack/connector (for Wall adapter) is provided on the Arduino boards?I'm curious because it appears to me that, for almost all situations, it wouldn't have any advantage (in sourced current, or in convenience) that isn't already provided by either a USB cable from a computer or else a USB wall charger cable.
Well perhaps one is building a portable project such as a robot or other mobile device where they want to power the board via a 12vdc battery?
Lefty
Batteries, OK, agreed. But...
@fungus:
For "power supplies", you might as well use a USB charger cable correct? Are there places where someone has an advantage using a different-voltage cable? (because after all, as you mentioned, it's being regulated to 5V).
( I do see one small advantage: As @Retrolefty mentions in the following page, with a different power source, you could potentially draw slightly more current than the USB-500mA: Arduino Forum )
giantsfan3:
Batteries, OK, agreed. But...@fungus:
For "power supplies", you might as well use a USB charger cable correct? Are there places where someone has an advantage using a different-voltage cable? (because after all, as you mentioned, it's being regulated to 5V).
Yes, but by being able to provide a higher voltage via the external power connector (7vdc to 12vdc) then that higher voltage is available via the Vin pin to power higher voltage components that the arduino can control, say small 12vdc motors, etc. So in some cases using a single higher voltage source lets the arduino on-board regulator supply the +5vdc, as well as having higher voltages to power other stuff controlled by the arduino and therefore is more convenient.
Lefty
Got it. Didn't know that VIN was shorted to the pre-regulated Power supply input voltage.
giantsfan3:
Got it. Didn't know that VIN was shorted to the pre-regulated Power supply input voltage.
LOL, I would have worded it 'wired to' rather then 'shorted to' 
I like to reserve the worded 'shorted' for more dynamic and dramatic situations, that usually involved magic smoke and cursing.
Lefty
PS: Looks like the S.F. Giants have shorted out and about to go up in smoke.
Aaaand.... go Giants!!