component

2N3904

Public Made by Adom

by adom

onsemi general-purpose NPN BJT, TO-92. 40 V, 200 mA, hFE 100-300, fT 300 MHz. Datasheet-verified.

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Made with KiCad 10.0 · needs KiCad 10.0 or later to open · KiCad file format 20260206
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docs 2n3904: re-etch, flat white mark read from pin 1 (service-occt 1.4.0) + chip hero · Ray 1mo ago
viewers cross-highlight symbol + footprint viewers · Ray 2mo ago
2n3904-etched.fit.json 2n3904: re-etch, flat white mark read from pin 1 (service-occt 1.4.0) + chip hero · Ray 1mo ago
2n3904-etched.glb 2n3904: re-etch, flat white mark read from pin 1 (service-occt 1.4.0) + chip hero · Ray 1mo ago
2n3904-etched.step 2n3904: re-etch, flat white mark read from pin 1 (service-occt 1.4.0) + chip hero · Ray 1mo ago
2N3904.adom-lbr.json 2N3904: validated Fusion/EAGLE library + adom-lbr hub, generated from this page's KiCad sources · Ray 2mo ago
2n3904.glb Publish 0.1.0 · Ray 2mo ago
2n3904.kicad_mod Publish 0.1.0 · Ray 2mo ago
2n3904.kicad_sym Publish 0.1.0 · Ray 2mo ago
2n3904.lbr add validated EAGLE .lbr (Fusion library) · Ray 2mo ago
2N3904.lbr 2N3904: validated Fusion/EAGLE library + adom-lbr hub, generated from this page's KiCad sources · Ray 2mo ago
2n3904.step add .step (Fusion 3D source) · Ray 2mo ago
package.json Publish 0.1.0 · Ray 2mo ago
page.json 2n3904: component.models_3d pose record per STEP (Z-up, seated z=0, pad-centre origin, identity binding) · Ray 28d ago
README.md 2n3904: laser-etched CAD + chip hero (factory 2.0.0 backfill) · Ray 1mo ago

2N3904

onsemi · NPN BJT (general purpose) · TO-92

The 2N3904 is the default general-purpose NPN bipolar transistor, in a TO-92 through-hole package. It switches and amplifies small signals up to about 200 mA and 40 V, with a current gain (hFE) of roughly 100 to 300 and a transition frequency near 300 MHz, so it works as a switch, a small-signal amplifier, or a logic-level buffer. The TO-92 leads are E, B, C in order (pin 1 = emitter). Its PNP complement is the 2N3906.

Pinout

Pin Name Type Function
1 E passive Emitter of the NPN transistor. VEBO breakdown 6.0 V. In TO-92 (viewed from the flat/front, leads down), lead 1 is Emitter.
2 B input Base of the NPN transistor. Controls collector current with hFE typ 100-300 at IC=10 mA, VCE=1.0 V. VBE(sat) ≤ 0.85 V at IC=10 mA, IB=1.0 mA.
3 C passive Collector of the NPN transistor. VCEO breakdown 40 V, VCBO breakdown 60 V, IC continuous max 200 mA. VCE(sat) ≤ 0.2 V at IC=10 mA, IB=1.0 mA.

Key specifications

Parameter Value
Type NPN bipolar transistor
Collector-emitter (VCEO) 40 V
Collector current (IC) 200 mA
DC gain (hFE) 100-300
Transition freq (fT) 300 MHz
Power dissipation 625 mW
Pinout E-B-C (pin 1 = emitter)
Package TO-92

Ordering variants

  • 2N3904BU (TO-92)
  • 2N3904TA (TO-92, ammo pack)

CAD (KiCad official)

  • Symbol: Transistor_BJT:2N3904
  • Footprint: Package_TO_SOT_THT:TO-92_Inline
  • 3D model: TO-92 (KiCad packages3D)
  • 3D model files: 2n3904-etched.step / 2n3904-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); 2n3904.step / 2n3904.glb are the bare package body.

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

  • Datasheet: onsemi datasheet (7 pp, sha256 39b20929e3d2d854, retrieved 2026-08-17, tier: manufacturer)
  • Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
  • CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF