Question

Frequency response of capacitive transducers is

• A. \( \text{High} \)
• B. \( \text{Medium} \)
• C. \( \text{Low} \)
• D. \( \text{Zero} \)

Hint:

The frequency response of a transducer is crucial for dynamic measurements. A transducer with a low frequency response will not accurately capture rapid changes in the measurand, leading to signal distortion. For applications involving fast-changing phenomena (e.g., high-frequency vibrations), transducers with a high frequency response are required. Conversely, for slowly varying or static measurements, a low frequency response is often sufficient.

Answer 1

The Correct Option is C

The frequency response of a transducer refers to its ability to accurately measure varying inputs over a range of frequencies.

1. Capacitive Transducer Principle: Capacitive transducers work by sensing changes in capacitance, typically due to changes in electrode distance or area.
2. Operational Speed: While the electrical changes in capacitance are fast, the mechanical changes that cause these capacitance variations (e.g., diaphragm displacement, movement of plates) often involve mechanical inertia.
3. Mechanical Limitations: Mechanical systems tend to have natural frequencies and limitations on how quickly they can respond to rapid changes in input. This inherent mechanical limitation often restricts the high-frequency response.
4. Output Circuitry: The associated electronic circuitry used to convert capacitance changes into a measurable voltage or current also has its own frequency limitations, but often the mechanical aspect is the primary limiting factor for overall frequency response.
5. Typical Applications: Capacitive transducers are excellent for static and quasi-static measurements, as well as relatively slow-changing dynamic measurements, but they are generally not preferred for very high-frequency applications compared to, for example, piezoelectric transducers.

Therefore, capacitive transducers typically have a low frequency response.