Power Transistor BD438 PNP, 4A TO-126

Power Transistor BD438 PNP, 4A TO-126

Transistors

Reference: TRBD438

Part.No: BD438

€1.20

In Stock

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The BD438 is a PNP power transistor in a TO-126 package, engineered for medium-power audio and voltage regulation applications. The complementary partner to the BD437, it delivers reliable switching and linear amplification in symmetrical output stages.

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Description
Product Details

BD438 PNP Power Transistor – Symmetrical Amplifier Output Stages

The BD438 is a robust PNP power transistor, the complementary counterpart to the NPN BD437. Rated for higher supply voltages and moderate collector currents, it is purpose-built for output stages in medium-power Hi-Fi amplifiers, voltage regulators, and push-pull switching circuits where symmetry and reliability are paramount.

Functions & Applications

Complementary PNP Design: Perfect matched pair with BD437 for symmetrical amplifier stages.
Medium Power Capability: Suitable for output stages driving 4Ω to 8Ω speaker loads in audio amplifiers.
TO-126 Package: Compact three-lead package with integrated heatsink mounting surface.
Robust Voltage Rating: Handles higher supply voltages in regulated and switching applications.
Audio-Grade Performance: Proven reliability in Hi-Fi amplifier and audio distribution circuits.

Technical Specifications

Parameter	Value / Specification
Transistor Type	BJT (Bipolar Junction Transistor)
Polarity / Channel	PNP
Package / Case	TO-126
Collector-Emitter Voltage (Vceo)	–80V
Max Collector Current (Ic)	4A
Power Dissipation (Pd)	12W
Mounting Type	Through-Hole with heatsink (TO-126)

Frequently Asked Questions

Q: Can I replace a failed BD438 with just one new transistor, or must I replace both BD437 and BD438?
A: It is strictly recommended to replace both BD437 and BD438 as a matched pair. Failure of one transistor often causes hidden stress damage to its complement, reducing amplifier reliability and risking further failure.

Q: What is the complementary NPN partner for BD438?
A: The complementary NPN transistor is the BD437. Together they form a matched pair for symmetrical push-pull amplifier output stages.

Notes

Always use as a matched pair with BD437. Both transistors should be replaced simultaneously if either fails. The TO-126 case requires a heatsink in medium-to-high-power audio applications.

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: PNP
Transistor Case Style: TO-126

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