Most transistors used today are NPN because this is the easiest type to make from silicon. The letters refer to the layers of semiconductor material used to make the transistor. 69.29 Kb TT 2222Abstract: 473m ceramic capacitors 17223 5.08 CN 40 C 223 K K 223 K 30 COG F VC 223 5.08 CN 15 C 100J DRM K 100 J 15 COG F TT, 100 K DRM K 100 K 15 COG F TT 229 5.08 CN 15 C 120 J DRM K 120 J 15 COG F TT 229 5.08 CN 15 C 120 K DRM K 120 K 15 COG F TT 229 5.08 CN 15 C 150 J DRM K 150 J 15 COG F TT 229 5.08 CN 15 C 150 K DRM K 150 K 15 COG F TT 229 5.08 CN 15 C 180 J DRM K 180 J 15 COG F TT 229 5.08 CN 15 C 180 K DRM K 180 K 15 COG F TT 229 5.08 - OCR Scan. Types of transistor There are two types of standard (bipolar junction) transistors, NPN and PNP, with different circuit symbols. TT 2222 Catalog Datasheet MFG & Type PDF Document Tags tt 2222Abstract: VC 5022-2 100 K 15 COG F TT 229 5.