If you take apart a standard car charger, you will find it's an incredibly simple circuit: it just puts a fuse and a resistor in series, which drop the voltage down to the appropriate level. Mine (for older Nokias) drop 14-ish volts down to about 4.5 volts.
Umm, not quite. The previous poster was right when he said it was a DC-DC converter. Basically this is a step-down switching power supply which converts 12V from your car (or 24V from your truck) to 5V for your phone. It's a small IC-based circuit, a little more complicated than a fuse and a resistor. Most phones, as you say, have a 3.6V battery, and a 5V supply is ideal to charge it.
I think the "single AA" chargers must use a "puck" -- that is, a voltage doubler. This is the same kind of circuitry used in LED flashlights that run a LED on two 1.5V alkalines (the LED needs perhaps 3.6 - 4.0 V to run).
True. The puck is a step-up DC-DC converter. They convert the 1.5V of the AA cell to about 5V to charge the phone. It won't fully charge the phone, but it will allow you to use it, and AAs are (usually) plentiful.
I a genuine emergency, where the phone is dead and you have nothing to lose, consider this: if I understand correctly, a phone that's off and close to dead still "pings" local towers, and that can be used to help locate you. You may or may not want to jeopardize that feature by messing with the phone. But if you're sure you have reception, and a few calls will get you out in a hurry, that may be an acceptable risk.
Sorry, not correct. When your phone is off, it's off. The only thing that is still running is the clock, which is used to activate an alarm clock if it is set.
My general solution is to buy a USB power cable for my phone. I used to have a Nokia 8210, and I had a couple of USB power cables lying around. If I didn't have my car charger or wall charger I could still plug the phone into a USB port on a PC or laptop and charge it up that way. I just got a Samsung phone, and as well as a wall charger it comes with a USB cable for getting data onto the phone which also happens to charge the phone. I strongly suggest that you get a cable like this as USB connectors are popping up all over the place (please keep reading).
I am migrating towards two connector types for my DC power requirements. Anderson PowerPoles for 12Vdc, and USB for 5V. Once you have built a couple of looms and adaptors with these connectors then it all starts getting fun.
Now, you can get wall adapters that run from 110-240Vac and provide 5Vdc on a USB outlet, and car adaptors that take 12-24Vdc and provide 5Vdc on a USB outlet...
and this:
The Boxwave VersaCharger Pro I found it when I was looking for this:
FreePlay Weza Which I sort of covet. If only it had PowerPoles instead of a cigarette lighter socket.
A
). I'm also have a couple of Y audio splitters allowing to charge 2-3 gadgets simultaneously.
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