About Transistor Part Number
Transistor part number can be confusing if you did not know how to read it. If you read the wrong part number you won’t be able find the exact data for the transistor specification. We were taught since from the college days was that a PNP B649 transistor (european code) is actually a 2SB649 (Japanese) and NPN C945 is 2SC945 and so on. The confusing part was that some semiconductor manufacturers came out with their own part number which is no more refering to standard code.
Take Philips HOT part number for example, it starts with the BU25XX, BU45XX and etc. If you do not have a data book or did not search the internet,you might think that it was a PNP transistor since the first part number started with “B”. Another i came across was the pnp darlington transistor with the part number of C516. If you try to locate the spec from a semiconductor data book i can guarantee that you will not find the spec if you search for 2sc516 or even c516. The actual part number was BC516. I do not understand why the manufacturer wants to remove the letter “B” from the transistor and make us as electronic repairer have a little bit tough time of searching for the exact part number.
Hope with these information i have just explained, you will be more flexible in locating the spec of transistors that come across your repair bench.