Why do ceramic capacitors have bias characteristics? What is the effect of ceramic materials on the bias characteristics of capacitors? ?
The condition of the electric field in the material will have an effect on the available capacity.
Without DC bias, the AC signal causes the "fixed" charge in the medium to commute back and forth, thereby affecting the electric field distribution within the material and "adsorbing" more of the charge. As the AC amplitude increases, the more the "charge" direction and the electric field are aligned, the additional electric field strength increases and the available capacity increases; but when the fixed electric field strength in the medium is consistent, the benefit is very small, so the AC capacity characteristics will be saturated.
Similarly, the DC bias causes fixed deflection of the fixed charge in the medium, so the performance of the material will deteriorate. The strong electric field with high bias makes the medium directionally polarized, and the material retreats to the situation of ordinary ceramics.
Therefore, when designing a capacitor, it is necessary to consider from material formulation, appearance shape design, electrode shape design and other aspects to minimize the influence of the electric field environment on the capacitance!