WEBVTT 1 00:00:02.142 --> 00:00:05.928 The microphone enables us to convert a mechanical vibration 2 00:00:05.929 --> 00:00:08.044 into an electrical signal. 3 00:00:08.045 --> 00:00:12.642 Its function is symmetrical to that of a loudspeaker in the chain of transmission. 4 00:00:12.643 --> 00:00:16.026 It is thus most often located at the beginning of this chain 5 00:00:16.027 --> 00:00:18.885 at the point of acquisition of data. 6 00:00:18.886 --> 00:00:24.292 In a dynamic microphone, there is a mobile membrane called the diaphragm 7 00:00:24.293 --> 00:00:29.804 a coil of copper wire, also mobile, as it is attached to the diaphragm 8 00:00:29.805 --> 00:00:34.141 and a permanent magnet, which remains fixed. 9 00:00:34.142 --> 00:00:38.372 The principle of functioning rests on the law of electromagnetic induction. 10 00:00:38.373 --> 00:00:42.630 The rapid displacement of the coil in relation to the magnet's field 11 00:00:42.631 --> 00:00:46.157 induces a voltage at the coil's poles. 12 00:00:46.158 --> 00:00:49.814 Since the mechanical vibration mirrors the sound vibration 13 00:00:49.815 --> 00:00:56.005 the electrical signal induced in the coil will also mirror the sound vibration. 14 00:00:56.006 --> 00:00:59.662 This type of microphone is easy to manufacture. 15 00:00:59.663 --> 00:01:04.207 It does not require any external source of energy and is quite robust 16 00:01:04.208 --> 00:01:07.290 notably for use on stage. 17 00:01:07.291 --> 00:01:10.869 The inertia of the coil-diaphragm couple, on the other hand 18 00:01:10.870 --> 00:01:15.989 makes it less sensitive to high pitches than is the electrostatic microphone.