sci.energy.hydrogen

jimp@ wrote:
> In Eeyore wrote:
>
>
>> jimp@ wrote:
>
>>> In Eeyore wrote:
>>>> Don Lancaster wrote:
>>>>> jimp@ wrote:
>>>>>
>>>>>> I don't care what symbol you use, the voltage in any circuit at any
>>>>>> instant in time is equal to the resistance times the current.
>>>>> resistance is a derived term that is the ratio of the voltage to the
>>>>> current.
>>>>>
>>>>> Only when it is constant or nearly constant does Ohm's Law even remotely
>>>>> apply.
>>>> Maybe you guys could agree that you need to use the term 'dynamic impedance' in
>>>> this case ?
>>> Why, "characteristic curve" is more widely used for nonlinear devices.
>
>> Not where I live. We talk of dynamic impedance when we need to know the V/I
>> characteristics.
>
> I'm using the language of US engineers, where do you live?
>
> Does your car have a trunk or a boot, tires or tyres, hood or bonnet?
>
It has been called dynamic impedance in the US for as long as I
remember and that is what we taught at the University. Assuming,
of course, that you consider California to be part of the US.

Remember that the dynamic impedance is the slope of the characteristic
curve. You can use either one but it is more useful to use the
dynamic impedance for AC calculations as that is what you will see.