Stethoscope with visual indicator and counter - has microphones flashing lamp and energising photodiode of frequency counter in synchronism with heartbeat

摘要

The diaphragm, (1) to be applied to the patient's body, communicates with a sound chamber (3) to which the usual acoustic earphones (9, 10) are attached. Also in acoustic connection with opposite sides of the chamber are two microphones (5, 6). The signal from the microphones flashes a lamp (12) at one edge of the sound chamber. At the opposite edge, and receiving light from the lamp, i a photodiode (15) which feeds impulses to a self-resetting frequency counter (16). In this way the rate and regularity of a person's heart-beat can be more quickly established than with a solely acoustic stethoscope. This is particularly important when large numbers of people are to be screened.