Re: transistor 2sc998
You can experimentally determine the emitter, base, and collector connections to the external terminals with a power supply which has a current limiter either adjustable or with a series resistor.
Set the power supply to 2 V and the short circuit current to 1 mA. The base will be the terminal that passes current to the other two terminals (collector and emitter). Then to determine which of the other two terminals is the collector and emitter you measure the voltage drop. The base-emitter is more heavily biased and will have the lower (0.65 V or so) voltage drop and the base-collector will have the larger voltage drop (0.8 - 1.0 V or so).
Then to make sure make a test circuit with the classical class A bias (resistor from emitter to ground, resistive voltage divider from the power supply point to the base, resistive load resistor. Measure the transistor terminal voltages and compare with your calculations. Then to double check, reverse the emitter and collector connections and the voltages will be way off due to the reverse beta being very low.