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RE: alignment of caps
From: mikey1[SMTP:mikey1-at-gladstone.uoregon.edu]
Sent: Monday, June 30, 1997 12:36 PM
To: tesla-at-poodle.pupman-dot-com
Subject: re; alignment of caps
Tesla List wrote:
>
> From: Richard[SMTP:esmit-at-ilink.nis.za]
>
> 1. When you want the right voltage for a capacitor you put them in serie and
> when you want the right capacitance you put them in paralelle. Which of
> these to figures is right.
>
> Fig.1
>
> ||
> |-----||-------| Total .005 uF
> | || |
> ------| |---------- TOTAL OUTPUT .0053 uF
> | || || || || |
> |-||--||-||-||-| Total .0003 uf
> || || || ||
>
>
>
> Fig.2 |
> || || || || Total .0053 uF
> |-||--||-||-||-|
> | || || || || |
> | |
> ---------| |-------------- TOTAL OUTPUT .01 uF
> | || || || || |
> |-||--||-||-||-| Total .0053 uF
> || || || ||
>
Well, Richard, they are actually both correct (although Fig.2 would be
at 0.0106 uF). An important thing to remember about capacitor circuits
is the difference between parallel and series connections.
In a parallel arrangement of capacitors, you essentially create one
larger capacitor, whose value is given by the addition of all values
connected in parallel. This is why both of your examples are correct;
you have provided the total values of the series caps, and all left to
do is to add up the values given in parallel.
In a series arrangement, however, the capacity decreases. The
capacitance of a number of capacitors connected in series is given by
taking the reciprocal of the additive reciprocals of all capacitors
connected in series, as given by the following formula:
Cseries=1/(1/C1+1/C2+1/C3+...1/Cn), where C1, C2, C3,...Cn are the
capacitance values of the series capacitors.
You will notice that the formulas for parallel and series circuits with
capacitors are similar to those used for resistors. Actually, they are
the same formulas, except that for parallel resistance you do the
reciprocal thing, and just add up the values for series. Just the
opposite of caps. Good Luck--Mike.
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