Electronics.The BC817-40W is a SOT-323 packaged, bipolar transistor manufactured by FUXINSEMI Electronics. This transistor is RoHS (Reduction of Hazardous Substances) compliant and uses silicon material for its construction. It has a maximum collector current of 40mA and a maximum collector-emitter voltage of 80V. It is suitable for general-purpose switching and amplifier applications, such as audio amplifiers, radio frequency amplifiers, and power management circuits, and may be used in cellular phones, TVs, DVD players, and other consumer electronics.