Capacitors, especially ceramic capacitors, and older designs such as paper capacitors, can absorb sound waves resulting in a microphonic effect. Vibration moves the plates, causing the capacitance to vary, in turn inducing AC current. Some dielectrics also generate piezoelectricity. The resulting interference is especially problematic in audio applications, potentially causing feedback or unintended recording. In the reverse microphonic effect, the varying electric field between the capacitor plates exerts a physical force, moving them as a speaker. This can generate audible sound, but drains energy and stresses the dielectric and the electrolyte, if any. COUNT 5
QSN1 What is the effect called when capacitors absorb sound waves? ANS1 microphonic effect QSN2 What value of a capacitor is varied when vibration moves the conducting plates?  ANS2 the capacitance QSN3 What sort of current is induced when the capacitance of a capacitor is altered? ANS3 AC current QSN4 In what type of applications is piezeoelectricity especially problematic? ANS4 audio applications QSN5 What is it called when a changing electric field existing between the conductive plates of a capacitor physically moves them? ANS5 the reverse microphonic effect