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Capacitors — Parallax Forums

Capacitors

ArchiverArchiver Posts: 46,084
edited 2003-09-28 20:01 in General Discussion
Hi people. I'm new here and wondering if you could help me out. I
have a capacitor which is fairily huge (5600 micro-farads) and has a
fairly high voltage rating considering it's capacitance). The thing
is it has THREE legs. I have no idea what to connect the third one
to. Does anyone here have any idea?

Thanks
James

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-09-28 17:05
    In a message dated 9/28/2003 8:51:27 AM Pacific Daylight Time,
    ensignkim113@y... writes:
    Hi people. I'm new here and wondering if you could help me out. I
    have a capacitor which is fairily huge (5600 micro-farads) and has a
    fairly high voltage rating considering it's capacitance). The thing
    is it has THREE legs. I have no idea what to connect the third one
    to. Does anyone here have any idea?
    ______________________________________________________-


    James,

    This is a Smile shoot, but, literally how physically large is this cap? Some
    caps that are physically large (standing 4" tall or better) have a third leg
    that is used to help secure the cap to the board and the third leg is not
    associated with the postive or negative lead.

    I have seen caps explode with incorrect circuit polarity applied, but have
    never seen this happen using an ohm meter. Perhaps you could connect one lead of

    an ohm meter to this third leg, and check if it has a direct connection to
    either the positve or negative leg. If no direct connection to either the
    positive or negative leg and the cap is indeed physically large (3 to 4" or more

    tall) the third lead MIGHT simply be a type of strain relief for mounting the
    cap......that is, it would provide additional mechanical support for the
    mounting
    of the cap.


    [noparse][[/noparse]Non-text portions of this message have been removed]
  • ArchiverArchiver Posts: 46,084
    edited 2003-09-28 18:00
    Sometimes they put two caps in one can with a common connection. If this is the
    case I would expect two values on the side stating capacitance. Can't think of
    another reason for three terminals.

    Leroy




    : Hi people. I'm new here and wondering if you could help me out. I
    : have a capacitor which is fairily huge (5600 micro-farads) and has a
    : fairly high voltage rating considering it's capacitance). The thing
    : is it has THREE legs. I have no idea what to connect the third one
    : to. Does anyone here have any idea?
    :
    : Thanks
    : James
    :
    :
    :
    : To UNSUBSCRIBE, just send mail to:
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    : from the same email address that you subscribed. Text in the Subject and Body
    of the message will be ignored.
    :
    :
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    :
    :
    :
  • ArchiverArchiver Posts: 46,084
    edited 2003-09-28 18:15
    Ground, for a metal can and mounting.

    Larry Gaminde


    Original Message
    From: "Leroy Hall" <leroy@f...>
    To: <basicstamps@yahoogroups.com>
    Sent: September 28, 2003 10:00 AM
    Subject: Re: [noparse][[/noparse]basicstamps] Capacitors


    > Sometimes they put two caps in one can with a common connection. If this
    is the
    > case I would expect two values on the side stating capacitance. Can't
    think of
    > another reason for three terminals.
    >
    > Leroy
    >
    >
    >
    >
    > : Hi people. I'm new here and wondering if you could help me out. I
    > : have a capacitor which is fairily huge (5600 micro-farads) and has a
    > : fairly high voltage rating considering it's capacitance). The thing
    > : is it has THREE legs. I have no idea what to connect the third one
    > : to. Does anyone here have any idea?
    > :
    > : Thanks
    > : James
    > :
    > :
    > :
    > : To UNSUBSCRIBE, just send mail to:
    > : basicstamps-unsubscribe@yahoogroups.com
    > : from the same email address that you subscribed. Text in the Subject
    and Body
    > of the message will be ignored.
    > :
    > :
    > : Your use of Yahoo! Groups is subject to
    http://docs.yahoo.com/info/terms/
    > :
    > :
    > :
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    Body of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2003-09-28 20:01
    Typically, a dual cap will have some markings like 5000/1000 to indicate the
    two values. It's most probably is a can shield and mounting lug.

    But I would suggest a little low-voltage charging experiment before you
    commit this thing to a high-current power supply transformer. Perhaps a
    9-volt battery with a 1k resistor in series would let you monitor the charge
    rate if you put a VOM across the cap leads. The other posting about
    potential explosion of a cap is fair warning. These things can go off like a
    small bomb and blow molten aluminum confetti all over the place. Been
    there... done that. I would never apply full current to an unknown cap until
    it goes through a slow charge and discharge. Nothing bad will happen with
    the 9 milliamps max current from a 9 volt batt and 1K resistor.

    Let be careful out there....

    Mike Sokol
    www.modernrecording.com
    mikes@m...


    " One should not increase, beyond what is necessary,
    the number of entities required to explain anything"...
    -William of Occam-
    Original Message
    From: "Stamps@C..." <stamps@c...>
    To: <basicstamps@yahoogroups.com>
    Sent: Sunday, September 28, 2003 1:15 PM
    Subject: Re: [noparse][[/noparse]basicstamps] Capacitors


    > Ground, for a metal can and mounting.
    >
    > Larry Gaminde
    >
    >
    >
    >
    Original Message
    > From: "Leroy Hall" <leroy@f...>
    > To: <basicstamps@yahoogroups.com>
    > Sent: September 28, 2003 10:00 AM
    > Subject: Re: [noparse][[/noparse]basicstamps] Capacitors
    >
    >
    > > Sometimes they put two caps in one can with a common connection. If
    this
    > is the
    > > case I would expect two values on the side stating capacitance. Can't
    > think of
    > > another reason for three terminals.
    > >
    > > Leroy
    > >
    > >
    > >
    > >
    > > : Hi people. I'm new here and wondering if you could help me out. I
    > > : have a capacitor which is fairily huge (5600 micro-farads) and has a
    > > : fairly high voltage rating considering it's capacitance). The thing
    > > : is it has THREE legs. I have no idea what to connect the third one
    > > : to. Does anyone here have any idea?
    > > :
    > > : Thanks
    > > : James
    > > :
    > > :
    > > :
    > > : To UNSUBSCRIBE, just send mail to:
    > > : basicstamps-unsubscribe@yahoogroups.com
    > > : from the same email address that you subscribed. Text in the Subject
    > and Body
    > > of the message will be ignored.
    > > :
    > > :
    > > : Your use of Yahoo! Groups is subject to
    > http://docs.yahoo.com/info/terms/
    > > :
    > > :
    > > :
    > >
    > >
    > >
    > > To UNSUBSCRIBE, just send mail to:
    > > basicstamps-unsubscribe@yahoogroups.com
    > > from the same email address that you subscribed. Text in the Subject
    and
    > Body of the message will be ignored.
    > >
    > >
    > > Your use of Yahoo! Groups is subject to
    http://docs.yahoo.com/info/terms/
    > >
    > >
    > >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    Body of the message will be ignored.
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    >
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    >
    >
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