Model SS - 46 bidirectional vibration meter is composed of vibration pick-up, integral amplifier and display instrument. When the object to be tested vibrates, the air gap of constant magnetic field formed between magnetic steel and magnetizer inside the vibration pick-up placed on the object to be tested will vibrate accordingly. The induced potential in relatively stationary state in air gap is integrated by the integral amplifier, then it becomes the voltage signal proportional to the vibration amplitude, and then after being amplified, detected and filtered, it outputs the DC voltage signal corresponding to amplitude value and it to the indicator, thus the size of the vibration is obtained.