How Does The Electrical Fittings Use A Pointer Multimeter To Judge The Quality Of Piezoelectric Ceramics?

Copper Terminal block How to use a pointer multimeter to judge the quality of piezoelectric ceramics?
Piezoelectric ceramics are a kind of artificial piezoelectric material. When subjected to external pressure, electric charges will be generated on both sides, and the amount of charge is proportional to the pressure. This phenomenon is called piezoelectric effect. Piezoelectric ceramics have piezoelectric effect, that is, they will deform under the action of an external electric field, so piezoelectric ceramics can be used as sound-generating elements.
Using the piezoelectric effect of piezoelectric ceramics, you can use a multimeter to judge their quality.
Lead two wires from the two poles of the piezoelectric ceramic, then place the ceramic flat on the table, connect the two leads to the two probes of the multimeter, turn the multimeter to the minimum current block of microampere, and then press the ceramic lightly with the eraser of a pencil. If the pointer of the multimeter swings obviously, it means that the ceramic is intact, otherwise, it means that it is damaged.