Pointer multimeter application examples
1 with a multimeter to determine the positive and negative speakers
First of all, the pointer multimeter dialled to DC 0 ~ 5mA block, and then the two pens were connected to the speaker to be tested on the two pads. Lightly press the speaker's paper cone, observe the multimeter pointer swing direction, if the pointer is positive deflection, the red pen is connected to the speaker negative, black pen is connected to the speaker positive. Conversely, the red pen is connected to the positive pole, the black pen is connected to the negative pole.
2 with a multimeter to determine the good and bad piezoelectric ceramics
Piezoelectric ceramic is a synthetic piezoelectric material. When subjected to external pressure, the two sides will produce an electric charge, the charge is proportional to the pressure, this phenomenon is known as the piezoelectric effect. Piezoelectric ceramics have piezoelectric effect, that is, under the action of the external electric field, will produce deformation, so the piezoelectric ceramic sheet can be used as a sound generating element.
The use of piezoelectric ceramic piece of piezoelectric effect, available multimeter to determine its good or bad. The two poles of the piezoelectric ceramic piece of lead out two wires, and then the ceramic piece of flat to the table, the two leads were connected to the multimeter two pens, the multimeter dialled to the * small current block, and then use the pencil eraser head lightly pressed the ceramic piece, if the multimeter pointer swing obviously, that the ceramic piece is intact, or else, the description of the damage has been done.
