1. S OUND E NHANCERS DEVICES THAT ENHANCE OUR ABILITIES TO HEAR

2. H EARING AIDS All hearing aids have the same basic parts. In the behind-the- ear hearing aid shown here, you can see the microphone, the tonehook or earhook, the volume control, the on/off switch and the battery door. The microphone picks up sounds and sends them to an amplifier that makes them louder. The hearing aid will make some pitches of sound louder than others, depending on the shape of the hearing loss. Your audiologist uses the hearing aid's internal controls or computer programming to adjust the sound for your needs.

3. When people refer to amplifiers, they're usually talking about stereo components or musical equipment. These are only a small portion of audio amplifiers. There are actually amplifiers all around us. You'll find them in televisions, computers, portable CD players and most other devices that use a speaker to produce sound.televisionscomputersCD playersspeaker Amplifiers

4. Sound waves move a microphone diaphragm back and forth, and the microphone translates this movement into an electrical signal. The electrical signal fluctuates (moves up and down) to represent the components of the sound wave.microphone A recorder programs this electrical signal as a pattern in some way -- as magnetic impulses on tape, for example, or as grooves in a record.tape As you can see, all the major components in this system are essentially translators: They take the signal in one form and put it into another. In the end, the sound signal is translated back into its original form, a physical sound wave. This is the job of the amplifier. It simply produces a more powerful version of the audio signal.

5. OSCILLOSCOPE An oscilloscope is an electronic measuring instrument that creates a visible two-dimensional graph of one or more electrical potential differences. One axis of the display normally represents time, making the instrument useful for displaying periodic signals.electronicmeasuring instrumentpotential differences Oscilloscopes are used in the sciences, medicine, engineering, telecommunications, and industry. These instruments are generally used for maintenance of electronic equipment and laboratory work. Special-purpose oscilloscopes may be used to display the waveform of a heartbeat (heart monitor).

6. U LTRASOUNDS Medical sonography is an ultrasound- based medical imaging technique used to visualize muscles, tendons, and many internal organs, to capture their size and structure. It uses high frequency sound waves and their echoes to make a picture of the inside of a body – organs, size, blood flow.medical imaging Ultrasounds are most commonly used to visualize babies in a mothers womb (stomach).