This part is a kind of semiconductor called BC237B.

Function of this product has Amplifier Transistors(NPN Silicon).

Manufacturers : ON

Image and pinout :

Some of the text within the PDF file :

BC237, BC237B, BC237C, BC239C Amplifier Transistors NPN Silicon Features http://onsemi.com COLLECTOR 1 2 BASE Symbol VCEO BC237 BC239 Collector −Emitter Voltage BC237 BC239 Collector −Emitter Voltage BC237 BC239 Collector Current − Continuous Total Power Dissipation @ TA = 25°C Derate above TA = 25°C Total Power Dissipation @ TA = 25°C Derate above TA = 25°C Operating and Storage Temperature Range IC PD PD TJ, Tstg VEBO 6.0 5.0 100 350 2.8 1.0 8.0 −55 to +150 mAdc mW mW/°C W mW/°C °C 12 3 VCES 50 30 Vdc TO−92 CASE 29 STYLE 17 45 25 Vdc Value Unit Vdc 3 EMITTER • Pb−Free Packages are Available* MAXIMUM RATINGS Rating Collector −Emitter Voltage MARKING DIAGRAM BC23 xy AYWW G G THERMAL CHARACTERISTICS Characteristic Thermal Resistance, Junction�� [ ... ]

BC237B PDF Datasheet Download