How an alternating current speaker works
1. AC sent through coil of wire attached to base of cone
2. Coil surrounds one pole of permanent magnet, surrounded by other pole
3. Current causes force on coil, causing cone to move
4. Current reverses, force acts in opposite direction, cone moves opposite way
5. Variations in cone make it vibrate, vibrates air around cone, creates variations in pressure, causes sound wave
