/diy/ - Do It Yourself

>dat heatsink

>>93275
It's necessary. That 7805 will put out 8 W or so under full 1 A load.

>>93284
There's no way that iPod is drawing one amp from USB.

>>93284
>>93299
Also a much smaller heatsink is capable of dissipating 8 watts.

>>93275
stabilizers, like that rumored to general a lot of heat, when their input voltage is quite high, like 18-24V

>>93299

No, but with a voltage regulator capable of delivering 1A, I'd rather not have it overheat if I ever plug anything else into it.

>>93301
I'd argue that it's a quite well-dimensioned heatsink for <8W, given that it's going into a hot car where ambient temperatures of 70 °C aren't inconceivable.

Furthermore, if it's accidentally short-circuited, the power dissipation might even rise toward 15W (picture related, about five minutes of continuous short-circuiting). That's a Tdelta of over 80 °C, and that's not even measuring close to the regulator. To really take that scenario into account, the heatsink should be even bigger (or more efficient).

Also, it was the first somewhat fitting heatsink in the box.

Furry, pull that dragon dildo out your ass and ram it down your throat.

>>93299

Especially since it's mandatory in the USB spec to shut off power if it even tries.

5V@500ma is 2.5W (assuming the regulator is *shorted*, otherwise, the dissipation is only for the voltage it's dropping, not the total input voltage), above which the host controller pulls your plug.

>at first I was like :|
>then I WOW THAT'S AMAZING

You say PCB funny.

Ground loops, ground loops everywhere.

All I hear in your video is

>wheeerererererererererememmmemrmerererer

>>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.

Damn FURRY, your voice is deeper than I would have guessed.

>rockbox
why would you abuse yourself like that

>>94113
I just look like I'm 12.

>>94115
Because it's far, far more flexible, usable and feature-packed than the original Apple firmware.

>>94115
>2011
>noit using rockbox whenever you can
ISHYG... oh wait, you're just a troll. The reasons are obvious to everyone.