Transistor BD139 NPN 80V, 1.5A, 12.5W, TO-126

Power Transistor BD139 NPN, 1.5A TO-126

Transistors

Reference: TRBD139

Part.No: BD139

€0.80

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The BD139 is a medium-power NPN Bipolar Junction Transistor (BJT) in a TO-126 package. Designed for audio amplifier output stages, voltage regulators and general-purpose driver circuits requiring higher current than small-signal transistors.

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Description
Product Details

BD139 Medium-Power Transistor - Built for Audio & Driver Stages

The BD139 is an NPN medium-power BJT housed in a TO-126 package, widely used in audio amplifier output stages, series voltage regulators and motor/relay driver circuits. Its 1.5A current rating and 12.5W dissipation make it a step up from small-signal transistors like the BC547 while remaining easy to mount on a small heatsink.

Functions & Applications

80V Vceo Rating: Comfortable voltage headroom for linear power supplies and audio circuits.
1.5A Collector Current: Handles moderate loads like small motors, relays and speaker driver stages.
TO-126 Package: Compatible with standard clip-on heatsinks for improved thermal performance.
Complementary PNP Available: Pairs with the BD140 for push-pull and complementary amplifier designs.

Technical Specifications

Parameter	Value / Specification
Transistor Type	BJT (Bipolar Junction Transistor)
Polarity / Channel	NPN
Package / Case	TO-126
Collector-Emitter Voltage (Vceo)	80V
Max Collector Current (Ic)	1.5A
Power Dissipation (Pd)	12.5W
Mounting Type	Through-Hole (THT)

Frequently Asked Questions

Q: Does the BD139 need a heatsink?
A: For currents above a few hundred mA or continuous operation near its 12.5W rating, a small clip-on heatsink on the TO-126 tab is recommended to keep junction temperature safe.

Q: What is the complementary PNP part for BD139?
A: The complementary PNP transistor is the BD140, commonly paired with the BD139 in push-pull amplifier and driver stages.

Note: Price refers to one (1) piece. The component is shipped in bulk without individual packaging.

Transistor Type: BJT (Bipolar Junction Transistor)
Transistor Polarity / Channel: NPN
Transistor Case Style: TO-126

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