BOJACK BD139 BJT transistor is a medium power booster transistor in front of high power tube output that can be widely used in analog circuits and digital circuits. Basic parameters: BD139 is available in a TO-126 package Transistor polarity: NPN Current ( Max): 1.5A Voltage (Max): 80V Power(Max): 12.5W Number of stitches: 3 Operating Temperature:-65 °C to +150 °C Surface Mount Device: Through Hole Mounting Lead-free environmental protection