# BC817

**Changjing** · Bipolar (BJT) · SOT-23

BC817 from Changjing, in a SOT-23. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.

## Pinout

| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | BASE | input | Base of the NPN transistor; emitter-base voltage is limited to 5 V (VEBO) and VBE(sat) is max 1.2 V at IC=500 mA, IB=50 mA. |
| 2 | EMITTER | passive | Emitter of the NPN transistor; carries the full collector current up to 0.5 A continuous with 5 V maximum emitter-base voltage. |
| 3 | COLLECTOR | passive | Collector of the NPN transistor; rated 45 V collector-emitter (VCEO), 50 V collector-base (VCBO), 0.5 A continuous current and 0.3 W dissipation. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Changjing |
| Package | SOT-23 |
| Category | Transistors/Thyristors |
| Pins | 3 |

## Electrical characteristics

Limits as printed in the datasheet (page.json `metadata.characteristics` carries them as data).

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Collector-Base Voltage | VCBO |  |  | 50 | V |  | 1 |
| Collector-Emitter Voltage | VCEO |  |  | 45 | V |  | 1 |
| Emitter-Base Voltage | VEBO |  |  | 5 | V |  | 1 |
| Collector Current -Continuous | IC |  |  | 0.5 | A |  | 1 |
| Collector Power Dissipation | PC |  |  | 0.3 | W |  | 1 |
| Junction Temperature | TJ |  |  | 150 | ℃ |  | 1 |
| Storage Temperature | Tstg | -55 |  | 150 | ℃ |  | 1 |
| Collector-emitter breakdown voltage | VCEO | 45 |  |  | V | IC= 10mA, IB=0 | 1 |
| Collector-base breakdown voltage | VCBO | 50 |  |  | V | IC= 10μA, IE=0 | 1 |
| Emitter-base breakdown voltage | VEBO | 5 |  |  | V | IE= 1μA, IC=0 | 1 |
| Collector cutoff current | ICBO |  |  | 0.1 | μA | VCB= 45 V, IE=0 | 1 |
| Emitter cutoff current | IEBO |  |  | 0.1 | μA | VEB= 4V, IC=0 | 1 |
| DC current gain hFE(1) | hFE(1) | 100 |  | 600 |  | VCE= 1V, IC= 100mA | 1 |
| DC current gain hFE(2) | hFE(2) | 40 |  |  |  | VCE= 1V, IC= 500mA | 1 |
| Collector-emitter saturation voltage | VCE(sat) |  |  | 0.7 | V | IC= 500mA, IB= 50mA | 1 |
| Base-emitter saturation voltage | VBE(sat) |  |  | 1.2 | V | IC= 500mA, IB= 50mA | 1 |
| Base-emitter voltage | VBE |  |  | 1.2 | V | VCE= 1 V, IC= 500mA | 1 |
| Collector capacitance | Cob |  |  | 10 | pF | VCB=10V, f=1MHz | 1 |
| Transition frequency | fT | 100 |  |  | MHz | VCE= 5 V, IC= 10mA, f=100MHz | 1 |

## CAD (KiCad official)

- Symbol: `BC817`
- Footprint: `Package_TO_SOT_SMD:SOT-23`
- 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files: `bc817-etched.step` / `bc817-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `bc817.step` / `bc817.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Changjing datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8579710464596492288) (2 pp, sha256 `39de72837d9ca295`, retrieved 2026-10-17, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-sonnet-5-5` (text+vision), consensus `claude-opus-5-5` (agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
- **CAD:** KiCad official libraries (CC-BY-SA 4.0).

[Datasheet PDF](docs/bc817-datasheet.pdf)