The 2N4037 is a PNP transistor manufactured by CDIL (Continental Device India Ltd.) and it is a general-purpose device used for many different purposes. It is a relatively low-power transistor, made of a PNP junction with a beta rating of around 70. It is commonly used for amplifying or switching low-level signals. Many devices with the 2N4037 include power, audio, digital, and RF applications. The 2N4037 is a through hole device, meaning it is soldered onto the PCB instead of being mounted onto it. It has a total of three pins, the emitter, collector and the base, which can be used for biasing or for switching.