Please help me understand this 12VDC - USB circuit. Answered
This ties into my earlier question about the large resistor (Thank you, Quercus austrina et al).
I'm an electronics newbie working on hacking a boombox into an under-cabinet kitchen radio. One of the things I want to do is provide USB power to charge my BlackBerry while I listen. I want to repurpose this car power adapter to do that. It has a cigarette lighter plug, two cig lighter jacks, and one USB port.
I have attempted to draw a schematic of the circuit as I understand it. This is my first schematic, so be gentle. Sorry about the small size. You may need to click on it and choose "Original Size" to see it more clearly.
Here are my questions:
1) There's a surface-mount resistor (R2) between the big scary "sandstone" one and the LED. The numbers on that resistor could be read as "102" or "201". If I understand correctly, it's either 1000ohms or 200ohms. That's a significant difference. Which is it likely to be?
2) Likewise, the ceramic disc capacitor (C2) appears to be labeled 104, but is very hard to read, since it's hidden behind the other two. There may be a dot after 104. Would it be .1µF, then?
3) Did I correctly decode the numbers on the group of four resistors that provide current to the USB data pins?
4) Here's the Big Question: If I remove the 7805 and everything to the left of it, and hook in 5VDC from a computer power supply, will it function?
Thank you for your consideration.