A TIP31 is a standard type of NPN bipolar junction transistor used for medium power applications. A TIP31 is complementary to a TIP32 PNP bipolar transistor. TIP31 transistors are designated as TIP31A, TIP31B, TIP31 to indicate increasing collector-base and collector-emitter breakdown voltage ratings. The TIP31 is packaged in a TO-220 case. TIP stands for Texas Instruments (Plastic) Power transistor. 31 is an arbitrary identifier. The series was listed in a December 1968 data sheet from Texas Instruments

A TIP31 is a standard type of NPN bipolar junction transistor used for medium power applications. A TIP31 is complementary to a TIP32 PNP bipolar transistor. TIP31 transistors are designated as TIP31A, TIP31B, TIP31 to indicate increasing collector-base and collector-emitter breakdown voltage ratings. The TIP31 is packaged in a TO-220 case. TIP stands for Texas Instruments (Plastic) Power transistor. 31 is an arbitrary identifier. The series was listed in a December 1968 data sheet from Texas Instruments