How many major components does the detector head consist of? What are they?

• A. Two main components: the sensor assembly and the transmitter assembly
• B. Three main components: sensor, transmitter, and power supply
• C. One main component: the detector element
• D. Four components: sensor, transmitter, housing, wiring

Answer: (A)

The detector head is built from two main parts: the sensor assembly and the transmitter assembly. The sensor assembly is where the gas actually interacts with a detection element, producing a signal that corresponds to the gas concentration. The transmitter assembly powers the sensor, conditions and amplifies that signal, and outputs a standardized reading to the control system (for example, a 4-20 mA or digital signal). In practice, the power supply is typically part of the transmitter assembly rather than a separate major component, and the housing and wiring are support elements rather than distinct functional blocks. This is why two major components—sensor and transmitter—best describe the detector head.