Power Transistor AD155 PNP, TO-3

Power Transistor AD155 PNP, TO-3

Transistors

Reference: TRAD155

Part.No: AD155

€2.34

In Stock

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The AD155 is a classic PNP Germanium Power Transistor in a TO-3 package. Designed for the output stages of vintage audio amplifiers and high-current switching applications where robust performance and direct heatsink mounting are essential.

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Description
Product Details

AD155 Germanium Power Transistor – Classic Output Stage Solution

The AD155 is a heavy-duty PNP germanium transistor, built for demanding audio and switching applications. Its robust TO-3 package allows direct bolting to large heatsinks, making it the preferred choice for vintage amplifier restoration and high-current output stages.

Functions & Applications

TO-3 Heatsink Mounting: Direct bolt-down design for efficient thermal management in high-power applications.
Germanium Construction: Warm, characteristic tone favored in vintage audio circuits and classic amplifier designs.
High Current Capability: Suitable for driving speakers and heavy inductive loads with protection.
Collector-Isolated Case: The TO-3 housing is internally connected to the collector; mica insulation required when mounting to a common heatsink.

Technical Specifications

Parameter	Value / Specification
Transistor Type	BJT (Bipolar Junction Transistor)
Polarity / Channel	PNP
Package / Case	TO-3
Mounting Type	TO-3 Bolt-Down

Frequently Asked Questions

Q: Do I need a mica insulator when mounting the AD155 to a heatsink?
A: Yes. The TO-3 case is internally connected to the collector, so you must use a mica insulator and thermal paste between the transistor and heatsink to prevent electrical short circuits.

Q: What is the complementary NPN germanium transistor?
A: The complementary NPN counterpart is the AD156, offering matched electrical characteristics for push-pull output stage designs.

Notes

Vintage germanium part; heat dissipation management and mica insulation are critical for reliable operation. Heatsink mounting is mandatory for all but the lightest loads.

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-3

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