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Subject: 
Re: lego cap, polarity, etc
Newsgroups: 
lugnet.robotics
Date: 
Wed, 28 Mar 2001 00:28:12 GMT
Original-From: 
Jim Choate <RAVAGE@EINSTEINavoidspam.SSZ.COM>
Viewed: 
609 times
  
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 your hand/face and potentialy catches fire. If you're lucky it will
only go 'pop' and spray yucky electrolyte over your work area.

Also, NEVER use an electrolytic that is leaking or has the top flat
surface 'bubbled' up. Both of these indicate internal damage and the cap
should be replaced.

This asymmetry in resistance is also what allows an electrolytic to store
charge from simply sitting. The brownian motion of the charges get trapped
preferentialy. It can provide a nasty surprise if you're not familiar
with it. And old 'joke' is to take an old, say 10,000mF, cap and get
somebody to put their finger (or better yet their tongue) across it.

On Tue, 27 Mar 2001, Andy Gombos wrote:

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.

    ____________________________________________________________________

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Message has 2 Replies:
  Re: lego cap, polarity, etc
 
(...) <snip> The polarity markings Andy Gombos was referring to are printed on the LEGO-compatible package itself. The LEGO "capacitor" is in fact an electrolytic cap with plenty of support circuitry, and I assure you there is no danger of blowing (...) (23 years ago, 29-Mar-01, to lugnet.robotics)
  Re: lego cap, polarity, etc
 
(...) This is generally true, but not as dire as you make it sound. (...) Actually, electrolyte is a good conductor of electricity (in any direction). It comprises one of the terminals in an electrolytic capacitor. The other terminal is aluminum, (...) (23 years ago, 31-Mar-01, to lugnet.robotics)

Message is in Reply To:
  Re: lego cap, polarity, etc
 
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 (...) (23 years ago, 27-Mar-01, to lugnet.robotics)

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