Ceramic Capacity Noise

However when a capacitor is mounted on a board the vibration increases and when the cycle of the amplitude reaches the audible frequency range 20hz 20khz of humans it can be heard as a noise.

Ceramic capacity noise. Most dielectrics of ceramic capacitors exhibit a characteristic identified as piezoelectric effects than can cause unexpected signals in certain circuits. Johnson nyquist noise thermal noise johnson noise or nyquist noise is the electronic noise generated by the thermal agitation of the charge carriers usually the electrons inside an electrical conductor at equilibrium which happens regardless of any applied voltage thermal noise is present in all electrical circuits and in sensitive electronic equipment such as radio receivers can. In some cases the piezoelectric effect may result in the appearance of electrical noise while in other cases. For example the noise sounds like a hum hiss or a high pitched tone.

Piezoelectric noise piezoelectric effect in mlccs multilayer ceramic chip capacitors mlccs multi layer ceramic capacitor have several advantages low equivalent series resistance esr low equivalent series inductance esl small size non polarized a disadvantage of the mlcc can be thepiezoelectric nature of the. When capacitors are used for power supply decoupling they serve two roles. An acoustic sound may be heard emanating from the capacitor itself.