hey guys, i just wanted to run a sanity check past you as i've got a basic hold of electronics to get me through but i just cannot find a solid answer to this question.
i have a bench power supply that is 12v @ 3Amp, is there any likely problems with me using this to power something that is say 12v @ 500Ma ?? i am under the impression that the extra 2.5 Amps the supply generates would either reduce the life of the item if not cause it to die pretty much immediately when connected?
i just want to check this before killing things when i start to use the supply plus it would help put my mind at rest when using "odd" power supply adaptors on items that are the same voltage but mismatched amperage.
im looking to try some things out with the arduino but some of the items i plan to control need 12v so i figured i would use my bench supply but as stated some of the items need a lot less current than the supply can provide.
The load will only use the amount of ampere's it "needs" and not more.
So it is not harmful that the power source can deliver more current (that is actualy a positive thing)
Correct, it's basic ohms law: Current = volts / resistance. Your load device (the arduino board and attached components) represents the 'resistance' and is what will determine how much current will be supplied by the power supply. You could have a 4 zillion amp power supply safely powering a single LED/resistor drawing just 20 ma from the supply. Just as one of your household power outlets can supply 7 amps for a vacuum cleaner, it can also power a simple night light using only 50 milliamps.
Kris:
i have a bench power supply that is 12v @ 3Amp,
3 Amps is the maximum that the supply can provide. When you connect your circuit, it will draw just what it needs, as you said about 500mA. This is fine and will cause no damage to anything.
plus it would help put my mind at rest when using "odd" power supply adaptors on items that are the same voltage but mismatched amperage.