Capacitive sensing instrument and method of using same

A sensing instrument includes a first electrode, a second electrode surrounding the first electrode, and a sensing module configured to sense a capacitance of a material by applying a voltage between the first electrode and the second electrode when the first electrode and the second electrode are adjacent to the material. A method of operating a sensing instrument includes applying a voltage between a first electrode and a second electrode when the first electrode and the second electrode are positioned adjacent a material. The second electrode surrounds the first electrode. The method further includes sensing a capacitance of the material based on the response of the material to the voltage. 一种感测仪器包括第一电极、围绕第一电极的第二电极以及感测模块，该感测模块被配置为通过当第一电极和第二电极邻近材料时在第一电极和第二电极之间施加电压来感测材料的电容。一种操作感测仪器的方法包括当第一电极和第二电极被定位成邻近材料时在第一电极和第二电极之间施加电压。第二电极围绕第一电极。该方法进一步包括基于材料对电压的响应来感测材料的电容。