Evgenij Barsukov wrote:
> Steve wrote:
>
>> John Bailey wrote:
>>
>>> Is that a fact and reason based answer or just a guess? A battery is
>>> not as efficient as a capacitor and there is a theorem from sophomore
>>> EE that "proves" no more than 1/2 the energy stored in a capacitor can
>>> be recovered.
>>
>>
>> Maybe at some EE correspondence school in outer Elbonia, but not
>> anywhere creditable. Most capacitors are nearly 100% efficient at low
>> frequency and moderate charge/discharge rates, I have no idea where
>> you came up with some "proof" that no more than half can be recovered.
>
>
> Sorry man, it might not be obvious, but this effect is true, easily
> provable based on the differential equation describing capacitor
> discharge and known to every electric engineer:
> http://www.smpstech.com/charge.htm
But we're not talking about the first-year method of charging a
capacitor from an ideal voltage source through a resistor are we? Nor
are we talking about discharging through a resistor to a purely
resistive load, are we?
>
> As other people have stated earlier, this applies only for straight
> linear capacitor / resistor systems without inductance.
>
> Switching systems with inductance is a different story and they can
> be 90-95% efficient.
EXACTLY my point when I made the first rebuttal!! There is no "theorem"
that states with any sort of generality that "no more than 1/2 the
energy stored in a capacitor can be recovered." In fact you can get
nearly 100% out as heat, should that be your goal (as it often is in
pulsed welding systems, for example). Period. End of story.
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