Condenser microphone
A microphone in which a thin diaphragm and a fixed backplate form a capacitor whose capacitance tracks sound pressure.
As the diaphragm moves, the gap to the backplate changes and so does the capacitance. With a polarising voltage across the capsule that becomes an output voltage, which a built-in amplifier has to boost before it can survive a cable run — hence phantom power. E. C. Wente built the principle at Bell Labs in 1916, and Neumann's U 47 of 1949 became the studio standard for vocals.
The diaphragm weighs next to nothing, so a condenser captures transients and treble better than a dynamic mic. The price is sensitivity to humidity, knocks and everything else in the room. The electret mic, developed at Bell Labs in 1962, carries a permanent charge and lives in practically every phone.