Capacitive Sensor: Advantages and Disadvantages

capacitive sensor
level sensing
sensor
measurement
advantage disadvantage

This page explores the advantages and disadvantages of capacitive sensors.

Definition of a Capacitive Sensor: A capacitive sensor is a device that uses capacitive coupling to detect and measure objects. It can detect conductive materials or materials with a dielectric constant different from air. For example, in liquid level sensing, changes in the liquid between two sensors alter the dielectric material, causing a variation in capacitance.

capacitive level sensing

The capacitance of two parallel plates with Area (‘A’) and separated by distance (‘d’) is expressed as follows:

capacitive sensing equation

A major application of capacitive sensors is level sensing, as mentioned above.

Advantages of Capacitive Sensors

Following are the advantages of Capacitive sensors :

  • It can be used to detect non-metallic targets.
  • It can detect through containers of certain types.
  • It is simple in construction and adjustable.
  • It can detect dense targets and liquids.
  • It is lower in cost.
  • It has higher sensitivity and can be operational with small magnitudes of force.
  • It can be used for the measurement of force, pressure, and humidity.
  • It has very good resolution (as low as 0.003 mm) and frequency response.

Disadvantages of Capacitive Sensors

Following are the disadvantages of Capacitive sensors:

  • It is very sensitive to changes in environmental conditions such as temperature and humidity. This will affect performance.
  • The measurement of capacitance is harder compared to the measurement of resistance.
  • Capacitive proximity sensors are not as accurate compared to inductive sensor types.
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capacitive sensor
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