Using the Power (Supply) of your Computer

[iccaros]

Jafo

If you understand the relation ship between voltage and current this would make more sense to you, voltage is a potential to do work, and has a force, so items like capacitor for instance is rated at how much potential can be across its leads before there is too much force and the electrons would jump the juncture inside the capacitor and cause it to heat, also since you now have a short current ramps as electrons are allowed to move,  which heat then destroys the item. Since current is the measurement of electrons moved over item, you can not have current with out a load, and with out potential

you did not see underrated power supplies burn up because of one or both of two reasons, most power supplies have a safety rating, which means that they are under rated for current and what is posted is the "SAFE" draw, cheep one not with standing. The rating for the device was MAX ratting and not actual running rating. Which means it did not draw as much current as it said it needs. Again this is a safety piece, manufactures do not want to get in trouble if the item you bought can draw X amount of current, even if in normal operation it does not use that much.

You do not need to understand any of this to really build pedals, you can understand relative voltage, and current can mean heat and be successful. IF you want to learn more, I suggest GEOFX or a course in electronics.. like this one http://jricher.com/NEETS/ (I would save these as they may go away)

to get in depth start with the first one, as it will confuse you to no end, leaving you asking more pointed questions...   and ask questions off that material, or geofx material.

EDIT
Sorry Defaced.. we posted at the same time..

[defaced]

Sorry Defaced.. we posted at the same time..

No worries, at lease we're saying the same thing   

To add to iccaros recommendations, physics text books generally cover this material as well - that's where I got my understand of the concepts.  The nice thing is that there are so many resources that you can try one after another until you find one that works for you. 

[jafo]

Thanks, all. I think I owe each of you a beer!

[jafo]

_I_ think PC power supplies are good for PCs and very little else. You can get batteries and small wall-warts everywhere.

I think you're right... I've been powering a TSF via USB, and it's full of random, low-frequency and -level noise which is there even with no input. I suspect that there's a certain amount of noise, period, plus noise for each inverter; I'm using three, in a fairly low-gain config -- higher gain (plus noise gate) would prolly cover it sufficiently, but I'm not a high-gain kinda guy. Maybe I'll mod it to two inverters, period, and see what that does, but I'm pretty sure it won't make that much of a difference.

[DavenPaget]

USB is noisy . Needs a whole lot of filtering .
Ask me why ? You wouldn't want to be sharing ground with your processor going at blazing speeds OR the harddisks .