Yes, that's exactly what I was asking. My "future" battery is the same siz= e, just the chemical reaction inside is a bit more efficient.=20 So, it would work just fine. It'd be dangerous has heck without extra prot= ection, but would work. =20 And this brings me to a better understanding: Current is used only when ne= eded. And according to Ohm's law I can vary the voltage at the expense of = current. And I'll take a stab at answering my next question. Given that my batter c= an supply so much energy, would it matter what voltage it is? If it were 1= volt and I needed 9 for my alarm clock, I could step it up to 9. If it we= re 1000 volts then I could step it down. Would it matter?` Actually, I don't know. -----Original Message----- From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of= Justin Richards Sent: Tuesday, October 22, 2013 4:44 PM To: Microcontroller discussion list - Public. Subject: Re: [OT] Thought experiment: Understanding volts vs amps Not sure exactly what you are asking so I will say some stuff. If you are asking if a hypothetical 9V battery that was capable of powering= a house could also be used to power a 9v device like a small 9V radio or 9= V remote control then the answer is yes. You would not be able to fit such= a battery inside the 9V radio or 9V remote but you could run wires to this= hypothetical battery. Also if you were to run a house off a hypothetical 9V battery the cables wo= uld need to be much heavier (thicker) as the current would be quite high. As the current increase the cable size needs to increase. Additionally to= run a house off this battery it would need to be connected to an inverter = to convert the 9V DC to AC and what ever level of voltage you area uses. For me it is 240 V. With regards to Volts and Amps. Power outlets in my house provide 240 volts and are rated at 10amps but any= device that I plug in will only draw the current it needs. Many people co= nfuse this point. So all the devices must be able to be driven by the 240v= olts. I could connect a light globe (240 watt ) for example that would dra= w only 1 amp while running or a heater rated at 2400 watts that would draw = 10 amps. Please feel free to rephrase your questions if I have failed to answer them= .. Regards justin On 22 October 2013 21:13, John Gardner wrote: > For some values of "neighborhood", a 'hood-day's worth of > > kW-Hrs in 9V battery form factor would make a nice warhead. > > "Energy Density" is a term encountered in connection with > > batteries, variously denominated in watt-hours per unit mass, > > or SI equivalent. > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive=20 > View/change your membership options at=20 > http://mailman.mit.edu/mailman/listinfo/piclist > -- 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 .