Mama77 Posted September 5, 2012 Report Posted September 5, 2012 [b]Introduction:[/b][color=#000000] A speaker is a device that converts an electronic signal into sound. The speaker you will build (see figure 1) consists of a Styrofoam or paper cup, a coil of wire, a permanent magnet, and a signal source. The electronic signal goes through the coil and creates a varying electromagnet. The attraction and repulsion between the electromagnet and the permanent magnet cause the cup to vibrate and produce sound.[/color][color=#000000] [img]http://cse.ssl.berkeley.edu/img/cupspker.gif[/img] [b]figure 1[/b][/color][color=#000000] [b]Purpose:[/b][/color][color=#000000] In this laboratory, you will explore how a speaker works.[/color][color=#000000] [b]Materials:[/b][/color][list] [*]1 permanent magnet [*]2 feet of wire [*]1 pencil [*]tape or glue [*]1 Styrofoam or paper cup [*]1 signal source (tape player) [*]1 plug with alligator clips for tape player [/list][color=#000000] [b]Procedure:[/b][/color][color=#000000] Assemble material as shown in figure 1.[/color][list] [*]Leaving about 10 centimeters on the end, wrap the wire around a pencil to make a wire coil and tape or glue it to the bottom of the cup. The coil should be about 1 centimeter in diameter and contain about 15 coils. [*]Strip the insulation off the ends of the wire. [*]Place the magnet on the wire coil. [*]Connect the signal source (tape player). [*]Adjust the apparatus until you get sound coming out of your speaker. [/list][color=#000000] [b]Conclusion[/b][/color][list] [*]Does the volume control on the tape player work on your speaker? [*]What kind of sound quality do you get out of your speaker? Compare the loudness and the clarity. [*]How does the sound quality compare with your string walkie talkie? [*]Explain how your speaker reproduce sound. [/list]
mettastar Posted September 5, 2012 Report Posted September 5, 2012 good post baaa ilantivi hobby kindha pettukovaliiii
Chandrabhai5 Posted September 5, 2012 Report Posted September 5, 2012 chinnapudu speaker lo magnets kosam speaker ni dismantle chesi magnet dngese vadini [img]http://i47.tinypic.com/vb0r9_th.gif[/img]
mettastar Posted September 5, 2012 Report Posted September 5, 2012 [img]http://www.electronicdesignworks.com/images/speakers_ani.gif[/img] The most important thing here is to note is that "iron metal" and "copper coil" both are attached to the diaphragm, and vibrates along with the diaphragm. Now as we apply small voltage to the coil, the coil magnetizes "iron metal" (simple electromagnetic concept). As you can see adjacent to "iron metal" there is a "permanent magnet" also present in assembly. Since north/south pole generated in the "iron metal" changes with the direction of current flow in "copper coil", and depending on this direction of current "iron metal" will either attract or repel "permanent magnet" as per simple magnetic law (same poles repel each other and opposite poles attract). As the amount of current and direction changes frequently the diaphragm vibrates rapidly which results into generation of sound.
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