Claims
- 1. A mobile telephone loudspeaker comprising a permanent magnet having a magnetic field and an air gap in which the magnetic field undergoes a reversal of orientation from a first end of the magent to a second end, a diaphragm, a first electrical coil for mechanical excitation that is movable with respect to the magnet and fixed to the diaphragm, the loudspeaker comprising a second electrical coil, wound so as to produce a counter electromotive force that is the reverse of the force produced by the first coil when they are both subjected to one and the same temporally variable electromagnetic or magnetic field, wherein the second coil is placed inside the field of the magnet and is fixedly attached to the first coil so as to be movable with respect to the magnet.
- 2. A mobile telephone loudspeaker according to claim 1, wherein the first and second coils each have a pair of power supply strands issuing side by side, the first coil going up to an end opposite the end of the second coil to which the pair of strands of this second coil goes up to.
Priority Claims (1)
Number |
Date |
Country |
Kind |
99 12996 |
Oct 1999 |
FR |
|
RELATED APPLICATION
[0001] This application is a division of application Ser. No. 09/691,684 filed Oct. 18, 2000, which claims priority to French Application No. 9912996 filed Oct. 19, 1999.
Divisions (1)
|
Number |
Date |
Country |
Parent |
09691684 |
Oct 2000 |
US |
Child |
10842774 |
May 2004 |
US |