Identifying the positive and negative terminals of a capacitor is crucial, especially when connecting it in a circuit. The orientation
is typically indicated on the capacitor itself. Here are common methods to determine the polarity of a capacitor:
Markings on the Capacitor:
Most electrolytic capacitors, which include tantalum and aluminum electrolytic capacitors, are polarized, meaning they have a
positive and a negative terminal. The capacitor's body usually has markings to indicate polarity. Look for:
Stripes or Bands: One side of the capacitor often has a stripe, band, or series of minus (-) symbols to indicate the negative side.
Arrows or Positive Signs: The positive side may be marked with a "+" sign or an arrow pointing towards the positive terminal.
Labeling:
Some capacitors have clear markings on the body indicating the positive and negative terminals. This can include labels such as
"Positive" or "Neg" next to the respective terminals.
Longer Lead:
In radial lead capacitors (where the leads come out from one end), the positive lead is often longer than the negative lead. The
longer lead is typically the positive one.
Smaller Lead Spacing:
In axial lead capacitors (where the leads come out from opposite ends), the negative lead may have a slightly wider spacing
between the leads than the positive lead.
Printed Text:
Some capacitors have printed text indicating the positive and negative terminals. Look for text such as "POS" or "NEG."
Symbols on the Circuit Board:
If the capacitor is soldered onto a circuit board, the circuit board may have symbols indicating the polarity of the capacitor. Look
for plus and minus signs or other polarity indicators.
Always follow the manufacturer's documentation and markings when connecting capacitors to ensure correct polarity.
Connecting a polarized capacitor backward can lead to failure, leakage, or even damage to the capacitor.
In contrast, non-polarized capacitors, such as ceramic capacitors and film capacitors, do not have a specific positive or negative
terminal. They can be connected in either direction in the circuit without affecting their performance.