What happens when an electrolytic cap is reversed:
Also, the anodic oxide dielectric is polar, and so are the
electrolytic capacitors (in contrast with the classical, electrostatic
capacitors), that is the capacitors must be connected with the correct
polarity as marked. """Connecting with reverse voltage injects hydrogen
ions through the oxide readily, causing high electrical conduction,
heating and reduction of the anodic oxide film."""" = explosion.
Non-polar (or bi-polar) devices can be made by using two anodes instead
of an anode and a cathode, or one could connect the positives or
negatives of two identical device together, then the other two terminals
would form a non-polar device.
What makes an electrolytic cap:
Electrolytic capacitors:
Electrolytic capacitors are capacitors in which one or both of the
"plates" is a non-metallic conductive substance, an electrolyte.
Electrolytes have lower conductivity than metals, so are only used in
capacitors when metallic plate is not practical, such as when the
dielectric surface is fragile or rough in shape or when ionic current is
required to maintain the dielectric integrity. The dielectric material
of electrolytic capacitors is produced from the anode metal itself in
what is known as the forming (or anodizing process. During this process,
current flows from the anode metal - which must be a valve metal such as
aluminum, niobium, tantalum, titanium, or silicon - through a conductive
bath of a special forming electrolyte to the bath cathode
Extracted from:
http://electrochem.cwru.edu/ed/encycl/art-c04-electr-cap.htm
Ramon
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Cicchiani, Arlene M.
Sent: Tuesday, October 24, 2006 2:37 PM
To: [log in to unmask]
Subject: [TN] capacitor polarity or not
As a trainer, how would I explain to a manufacturer, in simple terms,
the reason some capacitors have polarity, and some do not.
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