"Ian Macmillan"
"Phil Allison"
>>
>>
>> Be instructive to connect a scope across the uncharged cap and observe
>> what really happens when the charged one is first connected. Try a
>> couple of
>> 1uF film caps.
>
>>
> What really happens depends on the resistance of the path between the
> charged and uncharged capacitors. Initially when connected the uncharged
> capacitor is at 0 volts, so the current that initially flows is E/R,
> asymtoting to zero when the capacitor voltages match. With your 1uF film
> caps, there could be an oscillation, particularly if you just shorted them
> together.
** That is the scenario posed in text book examples of the question.
Often the poor student is also asked to assume the capacitors are ideal.
This really throws 'em.
If you just short the
> capacitors together, the resistance is in the connection or internal in
> the
> caps - its low and the current is high but it works out the same.
** In practical caps, the high frequency ESR and Q values are crucial to the outcome.
Plus the series inductance of the parallel assembly.
I am
> unhappy with my piece which was badly done, and I'll re-do it in due
> course.
** Please don't lose any sleep over it .
Be assured, others have.....
As to the point of it, obviously none for you, but could be relevant for
> others.
> By the way, your response also has a math error.
** Did I use a " * " where I should have used a " ^ " ?
Where is the usenet etiquette on this convention published ?
I normally avoid any chance of mis-interpretations takes and just write the word "squared".
.... Phil