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On 08/06/2014 07:36 AM, Bob Sciamanda wrote:
Perhaps this is a correctly simulated instance of "Mandated EnergyMore-or-less everybody assumes that, but it's not necessarily
Dissipation". EG., when a battery charges a capacitor, 1/2 of the
battery-produced energy must be dissipated.
true!
A whole lot of very smart people have gotten that wrong
over the years.
If we are clever, we can dissipate a whole lot less than
half of the energy. Proof by construction:
A battery, by definition, is a collection of /cells/.
Assume all N cells are in series. Assume we have access
to the individual cells. Let the cell voltage be u (small
u) while the battery voltage is V (big V) where V = N u.
Charge the capacitor step by step. Start by hooking it
up to just one cell. This moves a charge (C u) across an
average voltage drop of u/2, so it dissipates energy on
the order of (C u^2/2). This is very small, since u is
small. /snip/