Transistor BF251 NPN, 25mA TO-72

Transistor BF251 NPN, 25mA TO-72

Transistors

Reference: TRBF251

Part.No: BF251

€1.20

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The BF251 is a silicon NPN RF transistor in a TO-72 metal-can package, designed for intermediate frequency (IF) and RF amplification in AM/FM receivers, TV tuners and AGC stages.

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Description
Product Details

BF251 RF/IF Transistor - Stable Gain for AM/FM Receivers

The BF251 is a silicon NPN bipolar transistor housed in a compact TO-72 metal can, purpose-built for RF and intermediate-frequency (IF) amplification in AM, FM and TV receivers. With a transition frequency around 300MHz and low junction capacitance, it delivers clean, stable gain in tuner front-ends and AGC-controlled IF strips, making it a popular choice for repairing or restoring vintage transistor radios and RF equipment.

Functions & Applications

RF/IF Optimized: Low collector capacitance (0.3pF) keeps signal loss minimal at high frequencies.
High Transition Frequency (ft ≈ 300MHz): Clean amplification well into the VHF range.
TO-72 Metal Can Package: Provides natural shielding and good heat dissipation for sensitive RF circuits.
AGC Compatible: Well suited to automatic gain control stages found in radio and TV tuners.
Legacy-Friendly Replacement: A practical silicon substitute when servicing older RF/IF stages in vintage receivers.

Technical Specifications

Parameter	Value / Specification
Transistor Type	BJT (Bipolar Junction Transistor)
Polarity / Channel	NPN
Package / Case	TO-72
Collector-Emitter Voltage (Vceo)	30V
Collector-Base Voltage (Vcbo)	30V
Max Collector Current (Ic)	25mA
Power Dissipation (Pc)	150mW
Transition Frequency (ft)	≈300MHz
DC Current Gain (hFE, min)	30

Frequently Asked Questions

Q: Can the BF251 be used in the IF stage of an AM radio (455kHz)?
A: Yes, its transition frequency of around 300MHz easily covers the requirements of a 455kHz AM IF stage, and its low noise makes it well suited to weak-signal amplification.

Q: Is the BF251 a good replacement for older germanium RF/IF transistors?
A: It is commonly used as a silicon substitute for older germanium RF/IF transistors in vintage radio repair, but check the TO-72 pinout against the original part before wiring it in, since older germanium types often used different case/lead layouts.

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-72
TO-92

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