Smoke detector | sensor | optical | 4-wire | 12 V | 15 mA | Sentek SD119-4
Code: SD119-4The optical smoke detector is a reliable fire detection solution designed for both residential and commercial premises, where early smoke detection is critical for preventing accidents.
The device operates on an advanced optical scattered-light principle, ensuring rapid smoke detection in the early stages of a fire while minimizing false alarms.
Its modern design, low power consumption, and SMD electronic board provide high reliability, stable operation, and long service life.-
Detection area:
• 100 m² – smoke detector
• 50 m² – temperature detector
Power consumption: ≤ 70 µA (max)
100 Ω + 3 V max.
560 Ω + 3 V max. (red LED in open circuit)
Reset voltage: < 1 V
Reset time: < 1 sec
Alarm indication: red LED (steady on)
Operating temperature: –10 °C … +50 °C
Relative humidity: 0–95 % RH (non-condensing)
Remote output: max 15 mA, with diode gate
Alarm signal contacts (4-wire model):
N/O or N/C, Form A
1.0A @ 30VDC / 0.5A @ 125VAC
Dimensions: Ø100 × 46 mm (with base)
Weight: 130 g (with base)
Housing material: flame-retardant ABS plasticFunctions and Operating Principle
The detector operates on the optical diffusion principle – when smoke particles enter the sensing chamber, they scatter a beam of light detected by a photodiode.
The device processes this signal using an advanced algorithm that distinguishes real smoke from dust or steam, minimizing false alarms.
An integrated temperature sensor enhances safety by detecting both slow-burning and fast-developing fires.Applications
For home users: safe installation in kitchens, hallways, bedrooms, or storage areas.
For electricians: easy installation, compatible with standard fire alarm panels.
For engineers: suitable for building automation and alarm systems, connectable to control modules or central safety networks.
For public spaces: offices, schools, hotels, warehouses, server rooms, and production facilities.
Advantages
Large detection area – up to 100 m² per unit
Low power consumption (≤70 µA)
Fast reset after alarm (<1 sec)
Integrated LED indicator for clear alarm signaling
Resistant to humidity and temperature variations (–10…+50 °C)
Easy to install and maintain (modular base)
High reliability with SMD technology board
Disadvantages
Not suitable for outdoor use (indoor installation only)
Not recommended for dusty or humid environments (e.g., saunas, workshops)
Requires periodic testing and maintenance (at least once per year)
Illustrative image may have been created using AI. The appearance of the product may differ slightly from the image shown. Please refer to the technical specification.The IP protection class indicates the device's resistance to environmental factors.

The first digit indicates protection against dust and solid objects.
The second digit indicates protection against moisture.First digit values:
X — Untested;
0 — No protection;
1 — Protected against solid objects larger than 50 mm;
2 — Protected against solid objects larger than 12.5 mm;
3 — Protected against solid objects larger than 1 mm;
4 — Protected against solid objects larger than 1 mm;
5 — Dust protected;
6 — Totally dustproof.
Second digit values:X — Untested;
0 — No protection;
1 — Protected against vertically falling water drops;
2 — Protected against water drops falling at a 15º angle;
3 — Protected against rain falling at a 60º angle;
4 — Protected against water splashes;
5 — Protected against water jets;
6 — Protected against large amounts of water;
7 — Protected against short-term immersion in water up to 1 meter deep;
8 — Protected against long-term immersion in water up to 3 meters deep.This product is marked with the CE label, which confirms that it complies with all applicable European Union directives and regulations. CE marking is not just a formality – it is an important indicator of quality and safety, ensuring that the product has been properly assessed, tested, and can be safely used throughout the EU market.
CE certification means that the product has been evaluated according to the main criteria:
Safety requirements – ensures that the product does not pose a risk to the user or the environment
Electromagnetic compatibility (EMC) – the device does not interfere with other equipment and is resistant to external disturbances
Environmental standards – complies with current ecological and material usage requirements
Operational reliability – the product is suitable for long-term use according to its intended purposeCE marking allows this product to:
be legally supplied and used in all European Union countries
ensure a high level of quality and safety
be used in residential, commercial, and industrial environmentsThe CE mark is a declaration of the manufacturer’s responsibility, confirming that the product complies with all applicable standards and has been assessed according to EU legislation.
What does this mean for you as a buyer?
Safe use in everyday activities
Reliable performance and reduced risk of failure
Compliance with EU standards and requirements
Suitability for professional solutions
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