The piezo-electric buzzer salesman is one of the most successful businessman of his time. Perhaps not economically, but he certainly got his product into more devices around the world than I personally would ever have wished for.
The buzzer is a simple device – a piece of flexible crystal which flexes itself when an electrical current is applied. Turn the current on and off in rapid succession, and you get a frequency. You attach that frequency to a spasming piece of metal or plastic, and you get movement of air. You move air, and you get a blaring obnoxious noise entering your ear, waking you up at 6:30 in the morning as a construction worker decided to put his vehicle in reverse not too far from your bedroom window. Continue reading