Unlike non-polarized capacitors, electrolytic capacitors must be installed with the correct polarity. Installing an electrolytic capacitor "backwards" will result in improper circuit performance, component damage and the real possibility of the capacitor exploding.
Things You'll Need
- Digital MultiMeter (DMM)
- Soldering iron
Electrolytic capacitor polarity is identified on its case. The most common electrolytic capacitor has a blue plastic sleeve around the case with a stripe marked (+) for the positive lead or (-) for the negative lead.
The next most common type is an axial case (one lead out each end) with the positive lead having a bead or solder ball at the positive end.
Using the circuit schematic and DMM, determine which side of the capacitor should be the negative connection. (Electrolytic capacitors most often have the negative end tied directly to circuit ground).
Using solder and soldering iron, connect the negative end of the electrolytic capacitor to the negative connection. Solder the positive end of the capacitor to the positive connection.
Electrolytic capacitors are heat sensitive, so minimize the time the soldering iron is in direct contact with the capacitor leads.
Allow solder to cool (several minutes) before touching the soldered connection.
When applying power to the circuit for the first time, be certain you are wearing safety glasses.
Tips & Warnings
- An improperly installed electrolytic capacitor may build up internal gas pressure and "explode" if the gas pressure exceeds the case strength. Exploding capacitors may release a spray of caustic acid or oil which is a skin and eye irritant. Exploding capacitors may pop open, throwing metal or plastic pieces and injuring people or causing short circuits.
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