/diy/ - Do It Yourself

>>93514
Gladly.

>>93524
This thing isn't USB compliant. It just uses a USB connector so that I wouldn't have to shred that part of the cable as well. Let me run the power dissipation down for you:

This device is designed to go into a car. I consider 15 V to be a good worst-case-scenario input voltage in cars.

It is a linear regulator taking that voltage down to 5 V during normal operation, and down to 0 V when short-circuited. Its current limit is 1A. During normal operation, it should thus be able to handle dissipating (15 - 5 V) * 1 A = 10 W. 8 W is a more realistic figure to count on, since most cars don't lie at 15 V.

I don't quite see where you get the 2.5 W from. 2.5 W is indeed the maximum power dissipation that the USB standard allows devices to utilise, but it has nothing at all to do with the power dissipated inside of the voltage regulator. Even if we were to limit ourselves to 500 mA, the regulator would still have to dissipate 5 W.

>>93536
The noise is just due to my rather long, unshielded microphone cable that's running parallel with some cables that aren't too friendly toward microphone-level signals.