S8050 is a three layer NPN device within the working range, the collector current IC is a function of the base current IB, a change in the base current giving a corresponding amplified change in the collector current for a given collector emitter voltage VCE.

It is an NPN low-power transistor. It is mainly used as a low-frequency and low-noise preamplifier

The S9013 is a medium-power NPN transistor used for general purpose switching and amplification. It features a high transition frequency of 140MHz, making it suitable for high-frequency applications. It also has a relatively large collector current capacity of 500mA.