How do stethoscopes work?
There are two types of commonly used stethoscopes, electronic and acoustic. Acoustic stethoscopes consist of a chest piece, two hollow air filled tubes and the ear pieces. There are normally two sides to the chest piece: the diaphragm, a plastic disk, and the bell, a hollow cup. When the diaphragm is placed against the patient, the sounds of the body vibrate the plastic disk and acoustic pressure waves are formed. These pressure waves travel up the hollow tubes to the listener’s ears. The diaphragm side of the chest piece is useful for transmitting high frequency sounds. If the bell is placed against the patient, the vibrations of the skin directly produce acoustic pressure waves that travel up the hollow tubes to the listener’s ears. The bell side of the chest piece is used to tramsmit low frquency sounds. Electronic stethoscopes function by amplifying body sounds and are somewhat more useful for diagnosing problems with a patient because of the increased volume of the sounds.
