A bimetallic detector is

A bimetallic detector is

• A. A heat detector that uses two metals with different expansion ratios and auto resetting
• B. A smoke detector using ionization
• C. A carbon monoxide detector
• D. A photoelectric detector

Answer: (A)

A bimetallic detector is a heat detector that uses two metals with different expansion rates. When heat from a fire raises the temperature, the metals expand at different speeds, causing the strip to bend and trigger a switch that sounds the alarm. Because the mechanism can return to its normal shape after cooling, the detector auto resets and is ready to respond again. This type is distinct from smoke detectors (ionization or photoelectric) and from carbon monoxide detectors, which respond to smoke particles or gas concentrations rather than directly to heat.

A bimetallic detector is a heat detector that uses two metals with different expansion rates. When heat from a fire raises the temperature, the metals expand at different speeds, causing the strip to bend and trigger a switch that sounds the alarm. Because the mechanism can return to its normal shape after cooling, the detector auto resets and is ready to respond again. This type is distinct from smoke detectors (ionization or photoelectric) and from carbon monoxide detectors, which respond to smoke particles or gas concentrations rather than directly to heat.