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The Stethoscope and Its Electronics

February 21, 2024

The Stethoscope and Their Electronics


Giving 19th Century Doctors the Ability to Hear a Broken Heart


There’s a Keystone in every great invention.


The stethoscope is a staple piece of equipment in any doctor’s practice. The French physician Renee Laennec is credited with inventing the stethoscope in 1816. His inspiration came when he was confronted by a plump, young female patient with a heart condition. Embarrassed at the thought of having to press his ear to her chest, Laennec rolled up a sheath of papers into a cylinder and applied it to her chest, with the result that he could clearly hear her heartbeat.

Laennec’s original stethoscope was a simple wooden hollow tube approximately 10 inches in length and one inch in diameter, with a tapered end to insert into the ear. The other end was flat and placed against the patient’s chest. This allowed Laennec to listen to the sounds of the heart and lungs more clearly. This design was revolutionary for its time and established the foundation for the development of the modern stethoscope used today. In 1819 Laennec published a groundbreaking book where he proved that by giving access to the internal sounds of breathing and blood flow, stethoscopes allowed pathology to be performed for the first time on living things. Ten years later, Nicholas Comins, a Scottish doctor, developed the first flexible stethoscope, and in 1852, New York physician George P. Cammann added two earpieces to Laennec’s design to provide binaural sounds. 

Today, modern stethoscopes often incorporate electronic components for improved functionality. These electronic stethoscopes can amplify sounds, filter out background noise, and even  transmit auscultation findings (the action of listening to sounds from the heartlungs, or other organs) for further analysis or documentation. Some electronic stethoscopes also have digital displays that display sound waves and provide additional information to the user.


These advancements enhance the capabilities of stethoscopes in medical practice. For example, stethoscopes with 40x sound amplification and active noise cancellation are being designed for clinicians who work in settings with background noise and need to listen to body sounds with precision, or regularly assess patients for abnormalities. Some stethoscopes have a full-color display and 3-lead ECT which can be used in screening, monitoring, or triaging patients in both inpatient and outpatient settings.

Digital stethoscopes also provide wireless listening without a headset via Bluetooth-enabled devices and can record, save and share data for second opinions or follow up. These also feature USB-C charging ports for rechargeable lithium-ion batteries that can last up to 60 hours of regular clinical use.

Medical devices such as stethoscopes, hospital equipment and much more were on display in early February at the 2024 Medical Design & Manufacturing West show in Anaheim. Keystone Electronics along with 1611 other exhibitors presented the latest in components, tools and cutting edge technology. Battery solutions, technology and designs for medical applications were just one of the popular session topics throughout the conference.

Battery holders, clips and contacts are just a few of the Keystone product categories found in today’s medical devices and equipment. Other Keystone products include: Battery Clips, Contacts  & Holders,  LED holders, spacers and lens caps; Fuse Clips and HoldersPCB test points and terminalsspacers and standoffspanel hardware and PCB plugs, pins, jacks, and sockets and more.