NPN Power Transistor BD 139

🛠️ Silicon NPN Power Transistor – BD139 (TO‑126 Package)

Overview

The BD139 is a robust medium-power NPN transistor housed in a TO‑126 (SOT‑32) package. It's suited for applications in audio amplifiers, general switching, motor drivers, and power stages. With a 1.5 A continuous current rating and 80 V breakdown voltage, it's a reliable choice for a wide range of electronics projects.

Key Features

• Collector current: up to 1.5 A (peak up to 3 A)

• Collector–Emitter voltage: 80 V maximum

• Complementary to PNP BD140 in push–pull designs 

• Audio amplifier drivers

• Motor and relay drivers

• High-current LED switching

• Voltage regulation and power management

• Complementary transistor stages (paired with BD140)

✅ Resources

1. 📄 Datasheet PDF (ST/Onsemi/Motorola):
   BD135/BD137/BD139 silicon NPN transistor specs edn.com+1en.wikipedia.org+1youtube.com+14alldatasheet.com+14alltransistors.com+14electroduino.com+1youtube.com+1mouser.com+6alltransistors.com+6my.centralsemi.com+6

2. 🎥 YouTube Tutorial:
   “BD139 Transistor Complete Details & Working Principle” – detailed overview and use cases mouser.com+15youtube.com+15components101.com+15