microphonic

Microphonic is an adjective used in electronics and physiology to describe phenomena or devices that are influenced by or capable of converting small mechanical vibrations into electrical signals. In electronics, a component is described as microphonic if mechanical energy from vibrations is transduced into an electrical signal, creating noise or an undesired signal in circuits. The term is also used for signals that arise from this mechanical-to-electrical conversion, as in cochlear microphonic potentials in auditory physiology, where hair cells in the inner ear produce receptor potentials in response to sound.

In practice, microphonic effects are most common in parts that can move or vibrate, such as vacuum tubes, transformers, and capacitors. Loose mounting, wind, or mechanical resonance can cause a device to act like a tiny microphone, generating hum, hiss, or squeal. This is a particular concern in guitar and hi-fi tube equipment, where preamp tubes, transformers, or other components may pick up chassis vibrations. Remedies include rigid mechanical mounting, damping materials, shielding, good solder joints, and selecting low-microphonic components.

In biology and physiology, the term cochlear microphonic refers to an electrical potential produced by hair cells in the cochlea in response to acoustic stimulation; it is often used to assess outer hair cell function and auditory transduction.

Etymology: from micro- meaning small and phone meaning sound. The concept encompasses both intentional microphone action in transducers and unintended vibration-induced signals in electronic systems.