INFLUENCE OF AN ELECTRIC FIELD ON DIAPHRAGM STABILITY AND VIBRATION IN A CONDENSER MICROPHONE

✍ Scribed by C. Rajalingham; R.B. Bhat

• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 183 KB
• Volume: 211
• Category: Article
• ISSN: 0022-460X
• DOI: 10.1006/jsvi.1997.1385

✦ Synopsis

The electric field due to the constant bias voltage between the diaphragm and the base plate of a condenser microphone introduces a deflection dependent load intensity on the diaphragm. Since this load intensity increases with deflection, the electric field has a destabilizing influence on the plate vibration. Considering the diaphragm as a clamped circular plate, the dependence of the steady deflection and the natural vibration of the plate on the strength of the electric field is investigated. The analysis shows that as the field strength increases, the steady deflection also increases and reaches a neutral equilibrium state corresponding to a critical value of the field strength. Any further increase in the field strength buckles the diaphragm on to the base plate. The electric field decreases the fundamental natural frequency of vibration which approaches zero as the field strength reaches its critical value.