Transistor BC173 NPN

Transistor BC173 NPN, 0.1A TO-92

Transistors

Reference: TRBC173

Part.No: BC173

€0.60

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The BC173 is a general-purpose NPN Bipolar Junction Transistor (BJT) in a TO-92 package. A classic low-noise, high-gain small-signal part, directly interchangeable with the widely available BC547 family.

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Description
Product Details

BC173 Small Signal NPN Transistor - Low Noise, High Gain

The BC173 is an NPN silicon planar epitaxial transistor from the classic BC171-BC178 family, built for small-signal amplification and low-power switching. It offers a wide hFE gain range and low noise performance, making it a solid choice for audio preamp stages, general amplification and simple switching circuits in hobbyist and educational projects.

Functions & Applications

Low Noise Design: Well suited for audio preamplifier stages and sensitive signal paths.
Wide hFE Range: Gain grouping from roughly 110 up to 800 depending on the A/B/C suffix, giving flexibility across designs.
Standard TO-92 Package: Compact through-hole part, easy to breadboard and hand-solder.
Direct Replacement Available: Functionally interchangeable with the modern BC547/BC548/BC549 family for easier sourcing.

Technical Specifications

Parameter	Value / Specification
Transistor Type	BJT (Bipolar Junction Transistor)
Polarity / Channel	NPN
Package / Case	TO-92
Collector-Emitter Voltage (Vceo)	25V
Max Collector Current (Ic)	0.1A (100mA)
Power Dissipation (Pd)	0.3W (300mW)
DC Current Gain (hFE)	110 - 800
Transition Frequency (ft)	150 MHz
Mounting Type	Through-Hole (THT)

Frequently Asked Questions

Q: Can the BC547 be used as a modern replacement for the BC173?
A: Yes, the BC173 can be directly replaced with the BC547, BC548, BC549 or BC550, which share the same NPN TO-92 form factor and similar electrical ratings.

Q: What is the maximum current and voltage the BC173 can handle?
A: The BC173 is rated for a maximum collector current of 0.1A and a maximum collector-emitter voltage of 25V, so it is intended for small-signal, low-power applications only.

Notes

This is a classic legacy general-purpose part (BC171-BC178 family) largely superseded by the modern BC547 series; functionally equivalent and a good drop-in substitute if BC173 stock is limited.

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-92

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