NOT_SURE_ABOUT_THIS
In the context of capacitive sensors, the terms “grounded” and “ungrounded” refer to the way the sensing electrode is connected to the system.
Let’s discuss the differences between grounded and ungrounded capacitive sensors in terms of their front-end requirements:
- Grounded Capacitive Sensors:
- Connection: The sensing electrode of a grounded capacitive sensor is connected to the ground reference of the system.
- Front-End Requirement: The front-end circuit for a grounded capacitive sensor typically involves a simpler design.
It may use a single-ended amplifier since the reference is the ground.
- Ungrounded Capacitive Sensors:
- Connection: The sensing electrode of an ungrounded capacitive sensor is not directly connected to the ground reference.
- Front-End Requirement: The front-end circuit for an ungrounded capacitive sensor is usually more complex.
It often involves a differential amplifier to measure the potential difference between the sensor electrode and the ground.
In summary, the choice between grounded and ungrounded capacitive sensors depends on the application requirements.
Grounded sensors are simpler to implement in terms of front-end circuitry, but ungrounded sensors may offer advantages in certain situations, such as when there is a need to isolate the sensor from the ground for safety or when dealing with specific noise conditions.
- Remember that for capacitive sensors, we have to distinguish always between:
- Grounded sensor, (remember about proximity sensors).
So this kind of sensor which has the requirement of having one of the two terminals referenced. - And the other type are a referenced sensors.
In this case we are completely free to choose the best readout topology, because we have no constraints about the grounding of one of the two terminals.
- Grounded sensor, (remember about proximity sensors).