The KTC815-O is manufactured in a plastic TO-92 case. When looking at the flat side with the leads pointed downward, the three leads emerging from the transistor are, from left to right, the emitter, base, and collector leads. Here is an image showing the pin diagram of this transistor.
Classification of hFE
The KTC815-O transistor can have a current gain of 70 to 240. The gain of the KTC815 will be in the range from 70 to 240, for the KTC815-Y it will be in the range from 70 to 240.
Complementary PNP transistor
The complementary PNP transistor to the KTC815-O is the KTA539-O.
SMD Version of KTC815-O transistor
The 2SC2712 (SOT-23), 2SC3803 (SOT-89), 2SC4116 (SOT-323), 2SC4738 (SOT-23), FJX945 (SOT-323), KTC3875 (SOT-23) and KTC3875S (SOT-23) is the SMD version of the KTC815-O transistor. These transistors are of the same type, have similar parameters and are designed for surface mounting.