AC to DC transformer question

I have a Casio keyboard that came with a 9v 850ma power adapter/transformer that got physically broken.
My question is:
Would i harm the key board using a power adapter/transformer that is rated at 9V and 1000ma??

Would the extra 150ma cause damage or will the keyboard only "eat" the power it needs?

No, it won't be a problem at all. Same principle as having an 850w PSU in your PC & upgrading to a 1000w unit.

edit, You aren't charging rechargeable batteries in the keyboard, correct?

No charging on this keyboard.

I wasn't thinking the larger adapter would hurt, but just needed a 2nd opinion.

DUSNOETOS said:

I have a Casio keyboard that came with a 9v 850ma power adapter/transformer that got physically broken.
My question is:
Would i harm the key board using a power adapter/transformer that is rated at 9V and 1000ma??

Would the extra 150ma cause damage or will the keyboard only "eat" the power it needs?

Click to expand...

The numbers you have quoted are the power rating on the transformer. In the most basic sense, transformer is nothing but two coils of wire that are not in contact. Energy flows from the primary coil to the secondary via an induced magnetic field (i.e coils exchange energy via the magnetic field).

The windings themselves heat up when a current flows through them. The power loss is given as P=VI. Note that these coils are insulated, and the insulator has a specific melting temperature. So the power limit set states that under continuous operation, the maximum power draw should not exceed VI (which is 9 x 1 =9W in your specific example).

So in principle, a transformer rated for a higher Wattage can be used for an application that requires a lower power draw. In other words, your replacement is perfectly safe.

Note that a transformer is an energy transducer, not a source. It produces no power of its own accord. The primary should be energized (by an AC signal) and the secondary responds. What you need to look for is that the ratio of turns on your original unit and your replacement unit are the same. The higher current rating on your replacement unit merely means that a)The insulation is better or b)the windings comprise of thicker wires.

Hope this helps.

S-N

Thanks for that techincal explanation, Super nade.