Description- BD139 is an NPN transistor that has a gain value of 40 to 160. The maximum amount of current that could flow through the Collector pin is 1.5A.  It can be used to control (On/Off) bigger loads that consume less than 1.5A. It also has a very less saturation voltage.

Specifications- -Transistor type  :  Medium power NPN transistor -Continuous collector current  :  1.5A -Collector-Emitter voltage  :  80 V -Collector-Base voltage  :  80V -Emitter Base Breakdown Voltage  :  5V -DC current gain  :  40 to 160 -Operating Temperature Range : - 65 to 150°C -Low saturation voltage

Applications / Suggested Uses - -RF Amplifiers -Switching circuits -Amplification circuits -Audio amplifiers -Load driver circuits