What is meant by "filtered" on a plug in transformer?

[jbargstenpe]

What is meant by "filtered" on a wall plug in transformer like the ones used replace batteries on electronic equipment?

Thanks...

 

[itsmoked]

jbargstenpe; More advertising glop. As it could mean any number of things including dumb'ed-down speak for something else entirely.

More info from you might help pinpoint what it is referring to.

A guess would be:

Filtered so noise from a switcher type wall-wart is largely reduced to the electronic equipment since often there is little or no filtering by a wallwart since the gizmo(radio) has it built in. Whereas a generic wall-wart may have filtering - smoothing components added so that a device that was designed to use batteries (and hence has no internal filtering) won't pass a bunch of buzzing out of its speakers (for example).

 

[jbargstenpe]

itsmoked,

That's kind of what I thought. I was going to use a wall-wart to power a LED light and someone told me that the "filtered" one was needed to insure correct voltage. That didn't make sense to me. Anyway, I'll just add a voltage regulator IC to the circuit to keep the voltage constant. Do you know any reason why or if the circuit needs a "filtered" wall-wart?

Thanks

 

[itsmoked]

If you are going to run a regulator just add a cap in front of the regular and follow the regulator's data sheet and you would not need a "filtered" wall-wart.

Filtering does not "provide correct voltage". The wall-wart's transformer and internal regulator system does that. You do not need any kind of (after)regulator or filtering to run a LED lamp from a specified DC voltage output wall-wart. If a wall-wart sez 12 volts it is 12VDC by virtue of a regulator and that will provide very low ripple output.

Now if a wall-wart states "unregulated" or 10-13VDC output or something like that, then the wall-warts output voltage will be a function of the load and will move all over. This is very rare and you generally won't run into them.

You must of course make sure your wall-wart puts out The voltage your LED lamp needs. If it is strange than you may need your own after regulator.

 

[jbargstenpe]

itsmoked,

Thanks for your help!!