What type of microphone has internal components similar to a loudspeaker?

A dynamic microphone operates exactly like a loudspeaker in reverse. Both devices contain a thin diaphragm attached to a coil of fine wire that sits within a strong magnetic field. When sound waves hit a dynamic microphone, they vibrate the diaphragm and the attached coil. Moving this coil through the magnetic field induces a small alternating electrical current that mimics the sound wave. In a loudspeaker, the process is reversed: electrical currents drive the coil to move the diaphragm and produce sound. Other microphone types use entirely different principles. Condenser and electret microphones use a variable capacitor to generate audio signals, while crystal microphones rely on the piezoelectric effect of certain crystals when physically stressed.