# RL1812A391K

**RUILON Shenzhen Ruilongyuan Elec** · Varistors · 1812

RL1812A391K from RUILON Shenzhen Ruilongyuan Elec, in a 1812. 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 | 1 | passive | One terminal of the bidirectional, symmetrical varistor (WB 0.60±0.25 mm end termination); for RL1812A391K the varistor voltage is 351~429 V at 1 mA, with max allowable voltage 250 VAC / 320 VDC. |
| 2 | 2 | passive | Second terminal of the bidirectional, symmetrical varistor, interchangeable with the other terminal; for RL1812A391K the varistor voltage is 351~429 V at 1 mA, with max allowable voltage 250 VAC / 320 VDC. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | RUILON Shenzhen Ruilongyuan Elec |
| Package | 1812 |
| Category | Circuit Protection |
| Pins | 2 |

## Electrical characteristics

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

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Varistor voltage V1mA | V1mA | 351 |  | 429 | V |  | 2 |
| Max allowable voltage (AC) | VAC |  |  | 250 | V |  | 2 |
| Max allowable voltage (DC) | VDC |  |  | 320 | V |  | 2 |
| Max energy |  |  |  | 2.3 | J | 10/1000μs | 2 |
| Max clamping voltage | VC |  |  | 675 | V | 8/20μs, IP = 10 A | 2 |
| Withstanding surge current | I |  |  | 400 | A | 8/20μs | 2 |
| Tolerance (K code) |  | -10 |  | 10 | % | Standard tolerance K: ±10% | 1 |
| Varistor voltage change after bias humidity | VV/VV | -10 |  | 10 | % | 90%RH, 40ºC, working voltage, 1000 hrs | 3 |
| Varistor voltage change after thermal shock | VV/VV | -10 |  | 10 | % | -40ºC to 85ºC, 30 min cycle, 5 cycles | 3 |
| Varistor voltage change after full load | VV/VV | -10 |  | 10 | % | Working voltage, 85ºC, 1000 hrs | 3 |
| Response time |  |  |  | 1 | ns | <1ns as printed | 3 |
| Operating temperature range |  | -55 |  | 125 | ℃ |  | 1 |
| Storage temperature range |  | 5 |  | 40 | ℃ | Storage; relative humidity up to 65% | 3 |

## CAD (KiCad official)

- Symbol: `RL1812A391K`
- Footprint: `Resistor_SMD:R_1812_4532Metric`
- 3D model: 1812 (KiCad packages3D, STEP)
- 3D model files: `rl1812a391k-etched.step` / `rl1812a391k-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `rl1812a391k.step` / `rl1812a391k.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [RUILON Shenzhen Ruilongyuan Elec datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8771471795071803392) (5 pp, sha256 `61703208a13c9353`, retrieved 2026-10-19, 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/rl1812a391k-datasheet.pdf)