I was thinking of a battery of the possible future, same size. The reason I came up with this was to help myself understand current and vo= ltage. I've read all of your posts. My future battery would be the same size. So this is what I understood: Yes, I could just plug it into my radio and it would work fine _as long as_= nothing in that circuit demanded too much current. Otherwise total meltdo= wn. But it wouldn't unless something happened like I dropped a penny acros= s two wires. This answers one of my questions. Just because the potential current is th= ere doesn't mean it would be used. In other words, my imaginary battery wo= uldn't melt the insides of my remote control. But that gives rise to another question. Resistors resist current, but jus= t because my battery could provide a massive amount of current, would I nee= d different resistors in a circuit that powered my alarm clock? No, based = on peoples responses. =20 Other responses. Based on Ohm's law, it doesn't matter very much that it i= s 9 volts. I could easily step it up or down as needed. If it went through a DC/AC convertor, I could plug it into my house. This leaves one question that I think I may need math to figure out: Are r= esistors in a circuit dependent on the peak amount of current that can be s= upplied? Or, as long as there are no short circuits (or similar) would the= y stay the same? =20 What if I wrapped a wire around a nail to make a magnet like in the beginne= r books and connected them to the + and - ? Obviously there'd be a very ho= t and very large meltdown. This leads me to believe, if this is true, that= experiments like this depend on the amount of current over time a battery = can produce. In my head I cannot yet figure out how to do that experiment = with a battery that can deliver that much power. Sometimes when I have trouble understanding things it helps to think in ext= remes. Lindy -----Original Message----- From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of= Robin Bussell Sent: Tuesday, October 22, 2013 4:45 PM To: Microcontroller discussion list - Public. Subject: RE: [OT] Thought experiment: Understanding volts vs amps Hi Lindy, What you are describing is a (very) theoretical high energy densit= y (lots of Watt hours inside) battery with a very very low internal resista= nce (it can deliver a lot of amps when the load is of sufficiently low resi= stance). So if you were to plug this into a remote control in place of an ordinary 9= V battery it would work fine, the remote would take only the tiny current i= t requires and the battery would be able to power it for a very long time i= ndeed (assuming the battery has zero self discharge). If you were to short circuit the battery with a hefty copper bar then it wo= uld deliver a huge amount of amps through the low resistance of the bar and= probably vaporise it with spectacular and lethal consequences. Definitely = not the sort of battery to carry in your pocket along with keys and small c= hange! =20 It could be used in place of a car battery if the starter motor and other e= lectronics were changed to operate on 9v, other applications would all depe= nd on whether 9V was enough voltage to operate the electronics or overcome = the resistance of the load. Power * time does work. Power is Volts * Amps. Volts provide the poke to push Amps through Ohms. Things get more complicated for AC and loads with capacitance or inductance= :) Cheers, Robin.=20 -----Original Message----- From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of= Lindy Mayfield Sent: 22 October 2013 13:22 To: Microcontroller discussion list - Public. Subject: [OT] Thought experiment: Understanding volts vs amps I've spent years, on and off, trying to understand what volts means and wha= t watts or amps or current means. Literally since I first opened a book ab= out electronics when I was small. I may perhaps be close. Given matter to energy conversion rules and laws, and adhering to all known= laws of physics... What if I had a 9 volt battery that could easily supply all the power neces= sary to my home for 1 year. Or power a small neighborhood for a day no mat= ter what the energy consumption... This would be indeed an efficient chemical battery, but given the right tec= hnology, it could be done, no? Given that: Could I plug that same 9 volt battery into something small, l= ike a TV remote control, or a hand-held radio? In place of a 9v battery th= at I can buy today? Without any changes to resistors, capacitors, transist= ors? No changes to the circuits? And further, could that same 9 volt battery be used anywhere a battery is r= equired, a car starter, a toy, an electric wheel chair, an electric train n= ormally powered by a diesel? Assuming that in some cases the voltage will = need to be changed? It's probably painfully obvious those are my questions, not any out of a bo= ok or for a class. :) Thanks! Lindy -- http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/chang= e your membership options at http://mailman.mit.edu/mailman/listinfo/piclis= t -- http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/chang= e your membership options at http://mailman.mit.edu/mailman/listinfo/piclis= t --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .