Equivalent circuits are always simply approximations
done to make applications feasible. Electrolytic
capacitors in general have high leakage behaviors.
That is a price we usually pay for making our parts
smaller and smaller. Over 60 years ago when I used
silvered mica capacitors in RF circuits I had quality
unmatched by the stuff we have today. However, to
make
that capacitor in a 10 microfarad, 100 volt capability
would take a device roughly as big as a house and cost

many thousands of dollars LOL. So we live with the
inferior electrolytics. We just have to know their
limitations.

--- Joe <aubug2@...> wrote:

> --- In microelectricitygermkiller2@yahoogroups.com,
> Don Hildreth
> <w6nrw2@...> wrote:
> >
> > What you say would be true for 'normal' capacitors
> in
> > series, but the approximate equivalent circuit of
> an
> > electrolytic capacitor is usually given as a
> capacitor
> > in parallel with a diode. Thus the effective
> capacity
> > would not be half. (I'll admit that I have never
> made
> > any detailed analysis to confirm that equivalent
> > circuit in great detail)
>
>
> Well - it's not 'usual' but is a reasonable
> approximation -
> when you account for the monumental amount of
> reverse
> current leakage - enough to kill the operation
> of 555's - &
> still pass factory specs.
>
> Joe.
>
>
> >
> > --- Bella Lugosi <batzcuz@...> wrote:
> >
> > > Thanks Don...for bringing it up, but you're
> missing
> > > Detail~
> > > CAPs in Series, function like RESISTORs in
> > > PARALLEL!
> > > [If 2 equal R's in parallel, or equal C's in
> > > series, gives 1/2]
> > >
> > > If you want to make a 10-mfd (NP) CAP, you
> will
> > > need to
> > > wire two 20-mfd Polarized Caps in Series
> > > (back-to-back).
> > > Placing two 10-mfd caps in series...will
> yield,
> > > only 5-mfd.
> > > Some (audio-freq/low signal) applications are
> not
> > > critical,
> > > and while nice to get NP performance...reality
> > > prevailes?
> > > Power-distribution & motors DO-NOT use
> > > non-polarized!
> > >
> > > Most electrolytic caps, were manufactured with
> > > negative
> > > connection to the outside of the caps physical
> > > package,
> > > which is best in HVDC applications with case
> > > grounded.
> > > It's not wise when placed in series (floating)
> no
> > > grounds!
> > > Ok, my point being...wire 2 caps (-) to
> (-)...not
> > > (+) to (+),
> > > which helps to isolate, contacting outer (-)
> can =
> > > zaps..!
> > >
> > > Also note, if two Caps are equal-capacity (not
> > > likely) you
> > > can then operate new/(NP) series combo-caps,
> at
> > > higher
> > > WVDC/(operating-voltage) than original cap
> > > specification.
> > > For safety reasons, cap cannot be assumed to
> be
> > > same
> > > capacity of any other-caps that it is being
> > > paired-up with.
> > > As a ckt. designer, if I placed 2 (35-wvdc)
> caps
> > > in series,
> > > then might run combos...up to maybe
> 50-vdc...not
> > > to 70!
> > >
> > > FYI: If CAP VALUES are NOT EQUAL, then for
> SAFETY
> > > in AC (signal) voltage distribution...never
> > > exceed, WVDC
> > > values identified for the lowest capacitor in
> > > series-string!
> > >
> > > Hope my simplified (equation free) version,
> was
> > > helpfull?
> > > Parallel Caps/(Series Resistor) math is very
> > > simple, but
> > > equations are not that easy to represent here
> via
> > > typing.
> > > [Refer to any elementry electronics book, with
> > > formulas]
> > >
> > > ^BATZCUZ^
> > >
> > > P.S. I know, thinking what does some little
> BAT
> > > know,
> > > about electronics theory...(LoL) we had SONAR
> > > First...
> > > took humans eons to discover Batz (midnight)
> > > Secrets.
> > > ========================================
> > >
> > > Don Hildreth <w6nrw2@...> wrote:
> > > Just because I haven't seen it mentioned
> here.
> > > And just because there may be thousands of
> polarized
> > > electrolytic capacitors out there for every
> > > available non-polarized (NP)electrolytic
> capacitor,
> > > the following is what to do to make an NP
> > > electrolytic
> > > if you only can find the polarized kind: Put two
> (2)
> > > equal value polarized Cs in series in polarity
> > > opposition. That is, connect the two + ends or
> the
> > > two minus ends together to get the series pair.
> > >
> > > BATZ: Connecting (-) to (-)
> > > Safer/(More-Betterest-?)!
> > >
> > > The resulting non-polarized C is equal to one of
> the
> > > pair and the combination is non-polarized.
> > >
> > > BATZ: This (new) series C+C capacitor is
> NOT=C...
> > > it's C/2 = half of what you strated out with,
> > > trust Bat/
> > > also this only holds true if both caps are
> equal
> > > "C"~!
> > >
> > >
> > >
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>
>
>
>
>


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