Capacitors are divided into polarized and non-polarized, and electrolytic capacitors are polarized capacitors, so in the practical application of electrolytic capacitors, they must be connected strictly according to polarity, and cannot accept reverse voltage, otherwise it will cause serious effects. The following article will tell the way to identify the positive and negative electrolytic capacitors.

I. Identification of positive and negative polarity of bolt type electrolytic capacitor
Bolt type aluminum electrolytic capacitors have clear positive and negative level markings on the casing, positive pole is indicated by "+" and negative pole is indicated by "-". Most of the bolt type capacitors have "+" and "-" marks engraved next to the terminals on the cover, as shown in the figure below.
1、Positive sleeve mark
2、Negative sleeve mark
3、The positive and negative pole of the cover plate

Second, the distinction between positive and negative electrodes of aluminum electrolytic capacitors
Solder lug aluminum electrolytic capacitor is also called bullhorn capacitor, currently all manufacturers choose the "negative pole marking", that is, the solder pin corresponding to the "-" marking of the sleeve is the negative pole. Most of them adopt "embossing" to identify the negative pole, and some electrolytic capacitor manufacturers directly print "+" and "-" on the rivet. logo.
1、Negative sleeve marking
2、Embossed logo of cover plate

Leaded structure electrolytic capacitor positive and negative identification method
The lead structure electrolytic capacitor also adopts "negative pole identification", that is, the lead corresponding to the "-" mark of the casing is negative pole. The long lead is the positive pole, and the short lead is the negative pole, as shown in the figure below.
1, negative casing identification
2、Lead length identification

Chip aluminum electrolytic capacitor positive and negative identification method
Chip aluminum electrolytic capacitor is also called chip aluminum electrolytic capacitor, there is no sleeve for chip aluminum electrolytic capacitor, so the capacity, voltage, positive and negative electrodes and other related information are printed on the bottom of the aluminum case.