BD139 NPN Audio Driver Transistor

BD139 NPN Audio Driver TransistorNPN Transistor Schematic Symbol

You may see these listed as BD139-10 or BD139-16.  This is similar to the gain grouping denoted by the C suffix on the BC549.  The -16 suffix indicates the higher gain grouping.  You can use either in this circuit.   Alternatives that will definitely work in this circuit are BD137, BD135.

Navigate Up