As shown in figure 1.The Quartz accelerometer's fixed fingers in the forcing cells are normally kept at the same potential as that of the movable frame. When the digital self-test input is activated, the sensor changes the voltage on the fixed fingers in these forcing cells on one side of the moving plate. This potential creates an attractive electrostatic force, causing the sensor to move toward those fixed fingers. The entire signal channel is active; therefore, the sensor displacement causes a change in XOUT. The sensor’s self-test function verifies normal operation of the sensor, interface electronics, and accelerometer channel electronics.