

| Subject: | Re: Fwd: RE: "Green" solar battery charger |
| From: | tom ring |
| Date: | Fri, 14 Nov 2003 17:01:32 -0600 |
Hmm, despite the "failure" of ohms law, we were able to use it in my 500 level (that would be graduate level to non engineers) radio frequency non-linear transistor design course, we were still able to get answers better that 1 percent accurate. Guess we were just lucky. I'm done with this topic on the list. Let's take it offline folks. On 14 Nov 2003 at 17:22, Daniel L. Katz wrote: > tom and david: > > i thought you guys were believers in ohm's "law". if 1 MV is applied > across an ideal ohms law resistor with a value of, say, 500,000 ohm (100 > ohm), characteristic of a very dry (soaked with salt water) human being, > the current would be 2 A (10,000 A), and the corresponding thermal power > would be 2 MW (10 GW). note that the average hydroelectric output of the > entire bonneville power administration is some 6 GW. of course, ohm's law > fails in such unfortunate circumstances. > > my absolutely final word on ohm's law: > > given an ordinary resistor we can accurately predict current for any given > applied voltage (using ohm's law); if we don't know the resistance before > hand, we can measure the current for one particular voltage and we have > completely solved the resistor problem (obviously, to some finite level of > precision). now, however, suppose the cuurent is measured for a given > applied voltage across a diode. as suggested, one could always use ohm's > law to compute an effective resistance at these particular values of > current and voltage. that same effective resistance, however, cannot be > used in ohm's "law" to accurately predict the current at another, > arbitrary applied voltage. ohm's law is a valid in the appropriate regime, > but fails otherwise. > > dlk > > > On Fri, 14 Nov 2003 15:15:53 -0600, tom ring <taring@TARING.ORG> wrote: > > >You missed a 0, it's 100 KW! Really woohoo! > > > >On 14 Nov 2003 at 15:31, David Beierl wrote: > > > >> At 05:56 AM 11/13/2003, Andrew Grebneff wrote: > >> >battery... or an electrocution! (a 100mA current of 1,000,000V will > >> >not even be felt). > >> > >> Woo-hoo -- wanna bet? That's ten kilowatts... > >> > >> ;) > >> d > >> > >> > >> -- > >> David Beierl -- dbeierl@attglobal.net > >> > > > > > > > >-------------------------------------------------- > > > >``If I had all the money I've spent on cars ... > > I'd spend it all on cars'' -- Scott Fisher > ------ Tom Ring K0TAR, ex-WA2PHW EN34hx 85 Westphalia GL Albert 96 Jetta GL The Intimidator taring@taring.org "It is better to go into a turn slow, and come out fast, than to go into a turn fast and come out dead." Stirling Moss
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