Hi everyone. I'm currently just beginning my studying for my HAM license, and had couple of questions... 1. when looking at different items, a battery, a lightbulb, my Nintendo DS, etc, the information about the electronic is different. For example, this battery I have here shows that it's 1.2volts, and 850 mAh. So, why does it show these two bits of information? Why not show watts? or just amps? (or mili-amps in this case is more practical) The same line of question for the lightbulb. the lightbulb has the watts printed on it, and it has the miiliAmps, but NOT mA hours, like the battery does. So the main question is, why do certain devices/items use certain information? what determines this? 2. My other question is.. how do I know if the information on the device/item is for it's input requirement to use the item, or it's output rating that it gives off? Is it one of those things where you just have to use logic, like a fan obviously isn't going to give off electrical current, so what's printed on it, MUST be what it requires to operate? What about for devices that do both, like chargers? I'm looking at a charger I have here, and it's "INPUT" is 4.6 v and 900mAmps. So is the term INPUT referring the amounts that it takes from the wall socket in order for it to charge the device? or is it the amount that it "INPUTS" to the device, from the wall? How do I know? Thanks everyone in advance, hopefully these questions aren't too remedial or silly..