Subject:
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Re: lego cap, polarity, etc
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Newsgroups:
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lugnet.robotics
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Date:
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Tue, 27 Mar 2001 23:31:15 GMT
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Original-From:
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Andy Gombos <gombos_2000@yahoo*saynotospam*.com>
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Viewed:
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542 times
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If I read correctly, it sounds as if there are + and - signs on the capacitor,
which would imply that there is something that would block an incorrect
polarity on the terminal. Maybe the diode and the 2 transistors on the board
do this, I do not know.
Andy
Bruce Boyes wrote:
> At 15:01 3/27/2001 -0800, David Powell wrote:
> >
> >
> > > A bridge only works with an AC input - it can't correct the polarity of a
> > > DC input. So the Lego cap either has an AC input possibly through a
> > > bridge or a DC input which is the correct polarity by means of its
> > connectors.
> >
> > Uh, a bridge wouldn't be very good if it didn't handle inputs that
> > switched polarities. A bridge should work just fine with a DC input of
> > any polarity (of course for any DC input, only half of the bridge is
> > actually being used).
>
> Right, what I was trying to say is that a bridge can't 'invert' a DC input
> of one polarity to make an output of another polarity - it can't "correct"
> anything, a diode can only conduct or not conduct. All a bridge can do is
> route the given DC input through one leg or the other of the bridge.
>
> Bruce
> ------- WWW.SYSTRONIX.COM ----------
> Real embedded Java and much more
> High speed 8051 systems
> +1-801-534-1017 Salt Lake City, USA
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Message has 2 Replies:
 | | RE: lego cap, polarity, etc
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| That's right - it only needs to protect the capacitor from wrong polarity, but does not have to compensate. Maybe the instructions simply say "if it doesn't work, rotate the connector 90 degrees". Maybe the LED gives some indication if it is (...) (23 years ago, 28-Mar-01, to lugnet.robotics)
| | | Re: lego cap, polarity, etc
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| No. DO NOT UNDER ANY CONDITION CONNECT AN ELECTROLYTIC (ie one with +/- on the terminals) IN REVERSE. The electrolyte is a high resistant in one direction only. The other direction is nearly a short. You may end up hurt as the capacitor blows up in (...) (23 years ago, 28-Mar-01, to lugnet.robotics)
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Message is in Reply To:
| | Re: lego cap, polarity, etc
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| (...) Right, what I was trying to say is that a bridge can't 'invert' a DC input of one polarity to make an output of another polarity - it can't "correct" anything, a diode can only conduct or not conduct. All a bridge can do is route the given DC (...) (23 years ago, 27-Mar-01, to lugnet.robotics)
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