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What type of capacitors can be tested using Keysight Polarity Check?

Electrolytic capacitors, commonly known as polarized capacitors, are easily tested using Keysight Polarity Check. Keysight Polarity Check uses a sensor plate, like Keysight TestJet, to determine if a polarized capacitor is in backwards. In general Keysight Polarity Check is used to test tantalum and aluminum Surface Mount Technology (SMT) capacitors as well as axial lead capacitors. You can use Keysight Polarity Check on radial capacitors as well but the manufacturer of the radial capacitor must have a consistent process for Keysight Polarity Check to be effective.

Here is more detailed information on radial capacitors -

In general, Keysight Polarity Check will not work well on radial capacitors. The limitation that is preventing the Keysight 3070 from testing radial capacitors reliably is the inconsistency in the manufacturing processes of the capacitors themselves. However, there are some radial capacitor manufacturers whose manufacturing processes are standardized so as to produce consistent, and testable parts. Three that we know of are Nichicon, United Chemicon and Panasonic.

The reason Keysight Polarity Check can test some radial capacitors and not others is due to the inconsistent manufacturing processes of the companies that make radial capacitors. Manufacturing radial capacitors consists of layering two sheets of foil (one is positive, the other is negative) and rolling them together. If this process is standardized, the foil attached to the negative lead will always be the outer of the two foils. In this case, when the Keysight Polarity Check probe couples to the capacitor, it always does so to the negative lead.

Vendors who make radial capacitors that are testable by Keysight Polarity Check trim the foil as they finish rolling it so the layer on the outside is always consistent (negative). Therefore, we know that the outside layer of the capacitor is negative and thus the Keysight Polarity Check probe will be able to couple to the capacitor "can". The intended advantage of this "trimming" process, for the manufacturer, is to create devices with tighter tolerances.

Consequently, if the manufacturing process is not standardized, then the positive lead may either be partially wrapped around the outside, or fully wrapped around the outside, which will lead to either unstable measurements or false failures for polarity check.