The principle of sound transmission with a stethoscope, the principle of sound transmission with a s

The tube transmits sound, and the sound energy is lost less in it because the spatial constraints cannot be diffused.

It must be that the vibration of the heart comes in from the diaphragm of the stethoscope and is reflected to the eardrum through the vibration of the internal gas. My dad was a doctor and never asked him this question. He's on a business trip now, so I can't ask you, so I'll do it first.

Sound travels faster in solids than in gases and is not easily distorted.

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Analysis: The reason why people hear sound is that the so-called "sound" is the mutual vibration and conduction between substances, such as air vibration, the eardrum in the human ear, etc., which is converted into brain current, and people "hear" sound. The frequency of vibrations that can be felt by the human ear is 20-20kHz.

Another criterion for people's perception of sound is volume, which is related to wavelength, and the intensity of normal people's hearing ranges from 0db to 140db.

In other words: the sound is too loud and too weak to be heard in the audio range, and the audio is too small (low-frequency waves) or too large (high-frequency waves) in the volume range to be heard.

The sound that people can hear is also related to the environment, and the human ear has a shielding effect, that is, strong sound can cover weak sound.

Sounds inside the human body, such as heartbeats, bowel sounds, crackles, and even blood flow, are not likely to be "heard" because the audio is too low or too low, or it is obscured by a noisy environment. The principle of the stethoscope is that the vibration conduction between substances participates in the aluminum film in the stethoscope, and the non-air alone changes the frequency and wavelength of the sound, reaching the "comfortable" range of the human ear, and at the same time blocking other sounds, "hearing" more clearly.

The core device of the stethoscope mainly includes 4 parts, pickup, amplification and filter circuit, processing chip and Bluetooth module. The main function of the pickup is to collect auscultation sounds. The amplification and filtering device is a "speaker" that amplifies the auscultation sound.

The processing chip is used to reduce the interference of noise and ensure that the ideal sound data is obtained.

Finally, the Bluetooth module transmits the sound signal to the computer for storage. The auscultation audio data collected by the Bluetooth stethoscope can be transmitted to the computer, and can also be connected to the hospital's HIS system to match the patient's medical records.

It is made use of two principles:

Vibration produces sound, and sound is vibrating. There's a vibrator on the front of the stethoscope. The human organ vibrates, and the stethoscope vibrating plate is vibrate. The vibrator vibrates to produce sound.

Sound can be transmitted in solids. So the sound produced by the vibrator is transmitted to the ear through the solid.

1. The principle of the stethoscope is that the vibration conduction between substances participates in the aluminum film in the stethoscope, and the non-air alone changes the frequency and wavelength of the sound, reaching the "comfortable" range of the human ear, and at the same time shielding other sounds, "hearing" more clearly.

2. The reason why people hear sound is that the so-called "sound" is the mutual vibration and conduction between substances, such as air vibration, the eardrum in the human ear, etc., which is converted into brain current, and people "hear" sound. The frequency of vibrations that can be felt by the human ear is 20-20kHz.

3. Stethoscope is the most commonly used diagnostic tool for internal and external gynecologist and pediatrician, and it is the symbol of physicians, and modern medicine began with the invention of stethoscope.

The principle of the stethoscope: Vibration produces sound, and sound is vibrating. There is a vibrating plate in front of the stethoscope, and the human organ vibrates, driving the stethoscope vibrating plate to vibrate, and the vibrating plate vibrates to produce sound, and the sound can be transmitted in the solid, so the sound produced by the vibrating plate is transmitted to the ear through the solid.

Stethoscope construction:

1. Ear end (ear piece): The size of the ear piece should be suitable for the doctor's own external ear canal, and the upper end of the metal tube attached to the ear end should be bent into an arc. Auscultate with the concave side of the curved tube anteriorly.

2. Spring part: it should be suitable for the size of the doctor's skull, and the tightness should be moderate. Some stethoscopes do not have a spring part, and if the ear piece does not fit into the ear cavity, it is easy to fall off, or the auscultation effect is poor, which is common in cardiovascular disease in the United States**.

3. Rubber tube: The wall of the tube should be thick (about 3mm) to reduce the added noise. The rubber tube should not be too soft so as not to affect the high-pitched sound.

The inner diameter of the rubber tube should be the same as that of the metal tube, about 3-4mm. The length of the rubber tube should be appropriate, the shorter the auscultation effect is better, but it is inconvenient to use when it is too short, and the total length from the ear end to the chest end is about equivalent to the length of the doctor's arm.

4. Chest end (chest piece): The smaller the outer diameter of the chest piece, the more accurately the part that produces the sound, and it is easy to be in close contact with the chest wall, but because of its small collection surface, the sound is also weak. The outer diameter of the chest piece is larger, and the weaker sound is easier to detect.

The front end of the stethoscope is a large area of the membrane cavity, after the sound wave in the body agitates the membrane cavity, the sealed gas in the stethoscope vibrates, and the end of the ear, due to the narrow cavity, the gas vibration amplitude is much larger than the front end, thereby amplifying the sound wave vibration in the patient's body.

Materials play an important role in sound, as sound travels through air or matter, and eventually disappears into heat. The transmission of sound waves has almost no attenuation in heavy metals, and is prone to attenuation in lighter metals or plastics, so high-grade stethoscopes must use heavy metals such as stainless steel and even titanium.