For someone with hearing loss, a hearing aid can be a miracle. Even though a hearing aid can’t restore someone’s hearing, it can open the door to the world once more. To hear your child laugh again, to be able to talk on the phone to the ones you love, or just to appreciate the world around you—we take all of these things for granted until we lose them and then suddenly get them back.
So what is this little miracle that restores hearing? The truth is that a hearing aid isn’t very complicated; it’s just a matter of putting together some important electronic parts in a way that gets the sound from the environment into the person’s ear, at a level at which the person can hear it.
A hearing aid basically has four working parts: a microphone, an amplifier, a speaker and a battery. It’s just that simple.
The microphone works like any other microphone; it picks up sound and converts it to electrical impulses. Your tape recorder (or digital recorder) works the same way. Since sound consists of varying pressure waves, what the microphone does is take those waves and change them into “matching” electrical signals.
The next part, the amplifier, does just what it sounds like it does: it amplifies, or increases, the volume of sound that the microphone picks up. Most of the time when someone says “amplifier” you think about your stereo system; a hearing aid amplifier works the same way.
An amplifier basically is an input-output device, and those two functions are separate. The input circuit is the part of the amplifier that receives the incoming signal and interprets it. Then the signal goes to the output circuit, which is powered by the battery. The output circuit is a complicated series of electronic components that convert the signal into sound waves that make sense to the human ear and brain. This part of the hearing aid must be very precise for it to work properly.
The third part of the hearing aid, the speaker, is very much like a speaker on your stereo. It’s obviously miniaturized, but the basic principle behind the technology is the same.
The speaker converts the electrical signal back into sound waves that the ear and then the brain can understand. This part of the hearing aid isn’t nearly as complicated as the output circuit of the amplifier.
The last part of the hearing aid is thebattery. Obviously a hearing aid battery is a very tiny thing. Just like a full sized battery, a hearing aid battery has a positive side and a negative side, and you must put it in correctly or it won’t provide power to the hearing aid.
There’s just one caveat to all of this: hearing aids don’t work for everyone, and not everyone can use the same kind of hearing aid. If you have no hearing left at all (or didn’t have any to begin with) a hearing aid isn’t going to do you any good.
But for the millions of people who are losing their hearing because of age, disease, or injury, a good hearing aid can mean the difference between isolation and a full, happy life.