Correct Answer:
B. The rotation of the impeller generates pulses, which are counted by a microcontroller and then converted into a digital readout of flow rate in litres per minute.
Explanation:
- A. Incorrect: While some flowmeters might use magnetic sensors, the generation of a magnetic field by the impeller itself does not directly convert into a digital readout without electronic processing.
- B. Correct: In an impeller-type flowmeter, the rotation of the impeller creates pulses as it interrupts or triggers a sensor (often magnetic or optical). These pulses are counted by a microcontroller, which then calculates the flow rate and displays it as a digital value in litres per minute.
- C. Incorrect: An impeller-type flowmeter does not produce a varying resistance; instead, it typically generates pulses related to the flow rate.
- D. Incorrect: While the impeller's rotation is related to the flow rate, the output is not directly digital; it requires processing (such as counting pulses) to convert the rotational speed into a digital flow rate display.
Correct Answer:
B. The rotation of the impeller generates pulses, which are counted by a microcontroller and then converted into a digital readout of flow rate in litres per minute.
Explanation:
- A. Incorrect: While some flowmeters might use magnetic sensors, the generation of a magnetic field by the impeller itself does not directly convert into a digital readout without electronic processing.
- B. Correct: In an impeller-type flowmeter, the rotation of the impeller creates pulses as it interrupts or triggers a sensor (often magnetic or optical). These pulses are counted by a microcontroller, which then calculates the flow rate and displays it as a digital value in litres per minute.
- C. Incorrect: An impeller-type flowmeter does not produce a varying resistance; instead, it typically generates pulses related to the flow rate.
- D. Incorrect: While the impeller's rotation is related to the flow rate, the output is not directly digital; it requires processing (such as counting pulses) to convert the rotational speed into a digital flow rate display.