An electronic stethoscope which is adapted to receive auscultatory sounds from a body, is adapted to transmit the auscultatory sounds to a user, or other medical device which is adapted to be powered by a battery. The stethoscope has a chestpiece adapted to utilized in cooperation with the body, an acoustical transducer cooperating with the chestpiece for receiving the auscultatory sounds and transforming the auscultatory sounds into an electrical input signal. The stethoscope or medical device has an electronic processor for processing the electrical signal. The stethoscope has a speaker for converting the electrical output signal into an acoustical output signal and an earpiece receiving the acoustical output signal and providing the acoustical output signal to the user. The chestpiece (or housing of the medical device) has a cavity adapted to contain the battery. A battery carriage is insertable into the cavity of the chestpiece and is adapted to receive the battery before the battery carriage is inserted into the cavity of the chestpiece or housing. The battery carriage provides electrical continuity from the positive terminal of the battery to power supply circuitry when the battery carriage is inserted into the cavity of the chestpiece or housing. The battery carriage receives the battery in only one orientation with the positive terminal of the battery coupled to the positive electrical connection.