ne telepnone is an electrical instrument Speaking to the transmitter makes its diaphragm(震动膜) vibrate. this varies the electric current, causing the receiver's diaphragm to vibrate. This duplicates the original soundThe telephone is an electrical instrument Speaking to the transmitter makes its diaphragm（震动膜） vibrate. This varies the electric current, causing the receiver’s diaphragm to vibrate. This duplicates the original sound