Which type of smoke detector uses ionization to detect smoke by ionizing the air in the sensing chamber?

Which type of smoke detector uses ionization to detect smoke by ionizing the air in the sensing chamber?

• A. Photoelectric Smoke Detector
• B. Heat Detector
• C. Ionization Smoke Detector
• D. Smoke Detector

Answer: (C)

Ionization smoke detectors work by establishing an electrical current in a sensing chamber whose air is ionized by a tiny radioactive source. The ionized air allows current to flow between two plates; when smoke enters the chamber, smoke particles attach to the ions, reducing the current and triggering the alarm. This setup responds quickly to small, fast-burning flames that produce a lot of microscopic smoke particles. Photoelectric detectors, by contrast, use a light beam and detect smoke by scattering or blocking that light. Heat detectors don’t sense smoke at all—they trigger when the ambient temperature climbs to a preset level. A generic “smoke detector” label isn’t specific to the ionization mechanism, so it wouldn’t pinpoint the detection method.

Ionization smoke detectors work by establishing an electrical current in a sensing chamber whose air is ionized by a tiny radioactive source. The ionized air allows current to flow between two plates; when smoke enters the chamber, smoke particles attach to the ions, reducing the current and triggering the alarm. This setup responds quickly to small, fast-burning flames that produce a lot of microscopic smoke particles. Photoelectric detectors, by contrast, use a light beam and detect smoke by scattering or blocking that light. Heat detectors don’t sense smoke at all—they trigger when the ambient temperature climbs to a preset level. A generic “smoke detector” label isn’t specific to the ionization mechanism, so it wouldn’t pinpoint the detection method.