Method and apparatus for self-calibration of capacitive sensors

A method for operating capacitive sensors, comprising the steps of:

• providing at least one capacitive sensor and at least one self-testing and calibration network, said capacitive sensor having plates, said plates including a suspended element and a pick-up plate, said suspended element capable of displacement relative to said pick-up plate by application of a force, said displacement and said force related by a spring constant;
• applying an AC input signal to one of said plates,
• providing force between said plates, said force capable of variation, and
• determining at least one operational characteristic of said capacitive sensor.

A method for determining gap distances between capacitive sensor plates, comprising the steps of:

• providing at least one capacitive sensor, said capacitive sensor having plates, said plates including a suspended element and a pick-up plate, said suspended element capable of displacement relative to said pick-up plate by application of a force, said displacement and said force related by a spring constant;
• applying an AC input signal for generating a displacement current across said capacitive sensor, said AC input signal applied to one of said plates;
• measuring a resulting output signal, and
• determining a gap distance between said plates from said resulting output signal.

A method for determining at least one operational charactertistic of capacitive sensors, comprising the steps of:

• providing at least one capacitive sensor, said capacitive sensor having plates, said plates including a suspended element and a pick-up plate, said suspended element capable of displacement relative to said pick-up plate by application of a force, said displacement and said force related by a spring constant;
• providing force between said plates, said force capable of variation;
• directing an optical beam onto said suspended element to generate a reflected beam;
• and
• detecting said reflected optical beam.