The 2SC3998 is a NPN silicon transistor manufactured by SPTECH and offered in the TO-3PL package. It has RoHS compliance. This transistor uses a high voltage and high current capacity NPN design and is suitable for use in switching applications, power amplifiers, and linear applications. It features low saturation voltage, low noise, wide operating temperature range, and has a maximum continuous collector current of 800 mA, and collector-emitter voltage (Vce) of 250 V. The 2SC3998 is widely used in oscillator circuits, inverters, converters, and low-power switching circuits.