The 2SA73 is a NPN transistors manufactured by Youtai, housed in a SOT-23-3 package. It is RoHS compliant, meaning it does not contain any hazardous materials in its construction. The collector-emitter voltage range of the 2SA73 is from -30V up to -60V, with a collector current rating of up to 800mA. In addition, it features a high hFE, fast switching times, and low saturation voltage. This makes it a suitable choice for use in general-purpose applications such as amplifiers, switching circuits, and other applications in need of a reliable and efficient NPN transistor.