The BC817-40W.115 is a NPN transistor manufactured by Nexperia. It is commonly used as a switch in electronic circuits as it can handle up to 500mA of collector current (Ic) and 80V of collector emitter voltage (Vce). It is also used as a small signal transistor amplifying or switching. It is widely used due to its low saturation voltage and fast switching time. The BC817-40W.115 is encapsulated in a 4-pin SOT-23 package.