Transistor AF105 PNP, Germanium RF TO-72

Transistor AF105 PNP, Germanium RF TO-72

Transistor AF105 PNP, Germanium RF TO-72

Transistor AF105 PNP, Germanium RF TO-72

Transistor AF105 PNP, Germanium RF TO-72

Transistors

Reference: TRAF105

Part.No: AF105

€1.20

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The AF105 is a classic PNP Germanium transistor in a TO-72 package with 4 leads. Originally designed for RF preamplification in vintage radio receivers and signal processing circuits, it delivers low noise and excellent linearity characteristic of germanium technology.

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Description
Product Details

AF105 Germanium PNP Transistor – Classic RF Preamplifier for Vintage Radio

The AF105 is a legendary germanium PNP transistor renowned for RF signal amplification in mid-20th century radio designs. With its characteristic low forward voltage drop (0.2–0.3V) and superior linearity, it remains a staple for hobbyists restoring vintage receivers, building low-noise audio preamplifiers, and experimenting with germanium circuit topologies.

Functions & Applications

Low Noise Figure: Germanium construction inherently produces less noise than silicon equivalents, ideal for weak-signal RF stages.
Shielded TO-72 Package: Four-lead configuration with integrated shield can minimizes electromagnetic interference in sensitive circuits.
Low Forward Voltage Drop: Typical 0.2–0.3V allows operation at lower bias voltages compared to silicon transistors.
Vintage Radio Restoration: Authentic choice for rebuilding 1960s–1970s AM/FM tuner and IF amplifier stages.

Technical Specifications

Parameter	Value / Specification
Transistor Type	BJT (Bipolar Junction Transistor)
Polarity / Channel	PNP
Package / Case	TO-72
Forward Voltage Drop (Vbe)	0.2–0.3V
Mounting Type	Through-Hole (THT), Shielded

Frequently Asked Questions

Q: What is the complementary NPN silicon equivalent for the AF105?
A: For modern silicon-based designs, the BF494 or BF245 can serve as RF preamplifier alternatives, though they will have a higher forward voltage drop (~0.6–0.7V) and different noise characteristics.

Q: Why does the AF105 have four leads if it is a PNP transistor?
A: The fourth lead is the shield connection, which should typically be grounded. This minimizes electromagnetic interference and improves RF performance in sensitive circuits.

Notes

Vintage germanium component; genuine NOS stock. Requires appropriate bias conditions for optimal RF performance; not suitable for direct substitution in modern silicon designs without circuit redesign. Ensure proper grounding of shield lead (pin 4).

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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