The MJD122T4 from STMicroelectronics is a Bipolar Junction Transistor with Emitter Base Voltage 5 V, Base Emitter Saturation Voltage 4.5 V, Emitter Cut off Current 2 mA, Collector Base Voltage 100 V, Collector Cut off Current 10 µA. Tags: Surface Mount, NPN Transistor. More details for MJD122T4 can be seen below.