About potential difference of the aluminum case and each electrode terminal
The aluminum case and cathode terminal may have the same potential because they are connected via an electrolyte (unstable resistance component).
There may be a potential difference between the case and the anode terminal because the anode terminal has an oxide film with high withstand voltage properties on the anode foil surface.
Although there appear to be examples of this aluminum case being used as an electrode in certain in-circuit testers (ICT), as is outlined above, this is an unstable connection and there is no guarantee of conduction. As such, we do not recommend this measurement method.
Not only is there the possibility of not being able to make proper judgments, there is also the possibility of a capacitor malfunction depending on the size of the current.
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