Transistor AF138 PNP, Germanium UHF TO-72

Transistor AF138 PNP, Germanium UHF TO-72

Transistor AF138 PNP, Germanium UHF TO-72

Transistor AF138 PNP, Germanium UHF TO-72

Transistor AF138 PNP, Germanium UHF TO-72

Transistors

Reference: TRAF138

Part.No: AF138

€1.40

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The AF138 is a vintage PNP germanium transistor in a shielded TO-72 package (4-lead), optimized for UHF tuning circuits and measurement equipment. Its built-in electromagnetic shielding minimizes RF noise in high-frequency amplification stages.

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Description
Product Details

AF138 Vintage PNP Germanium Transistor – UHF Tuner & RF Amplification

The AF138 is a PNP germanium transistor from the classic 13x series, purpose-built for UHF television tuners and RF measurement circuits. Its 4-lead shielded TO-72 package provides inherent electromagnetic isolation, making it reliable for high-frequency amplification where noise rejection is critical.

Functions & Applications

Shielded 4-Lead Package: Built-in Faraday cage (TO-72) reduces RF interference and oscillation.
Germanium Construction: Excellent low-frequency gain and smooth response typical of vintage germanium devices.
UHF Optimized: Stable amplification across the UHF band for tuner and measurement applications.
High-Frequency Stability: Minimal frequency drift, restoring oscillation stability in vintage circuits when replaced.

Technical Specifications

Parameter	Value / Specification
Transistor Type	BJT (Bipolar Junction Transistor)
Polarity / Channel	PNP
Package / Case	TO-72
Polarity	PNP
Material	Germanium
Package Type	TO-72 (4-Lead Shielded)
Application	UHF RF Amplification

Frequently Asked Questions

Q: What does the fourth lead in TO-72 do?
A: The fourth lead is connected to the internal shield can, providing electromagnetic isolation. Ground it to the chassis or RF common point to maximize noise rejection in high-frequency circuits.

Q: Is AF138 still in production?
A: No, AF138 is a vintage/NOS (New Old Stock) part. It is no longer manufactured but remains highly sought for restoring classic UHF tuners and measurement instruments where original performance and frequency stability are important.

Notes

Vintage NOS (New Old Stock) part. Sought-after for restoring classic UHF television tuners and measurement equipment. Handle with care; germanium transistors are temperature-sensitive and can age if exposed to extreme heat or humidity.

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-72

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