The result shows, under different vibration mode, equivalentparallel capacitance and resistance are not constant value. There is negative damp effect in transducer system at the operating mode.
The output power mechanism of a separately excited DC motor can be equivalent to a variable resistance, which is parallel with the armature winding of the motor.
However, since the cable leakage resistance (RL) is in parallel with RS, the actual measured resistance (RM) is reduced, as shown in the parallelequivalent circuit of Figure 2-34b.