18. Dao động cơ học

Nguyên tắc con

1. Make the object vibrate
2. If it already vibrates, raise the frequency, even into the ultrasonic range
3. Exploit the object's resonant frequency
4. Replace mechanical vibrators with piezoelectric ones

Ví dụ

• An ultrasonic cleaner
• A concrete vibrator that settles the mix
• An electric toothbrush that shakes plaque loose

Ứng dụng theo lĩnh vực

• medical: Scraping off tartar can damage gums and enamel. A tip vibrating at ultrasonic frequency breaks the tartar into fragments with much less force.
• mechanical: Belt conveyors have many wearing parts. A tray shaken at its resonant frequency moves parts forward in small hops with little power.
• electronics: A buzzer built from a coil and metal plate is bulky and power-hungry. A vibrating piezoelectric element makes the sound in a thin, low-power part.
• everyday: A sound alert is awkward where quiet is needed. Making the device body vibrate tells only the person holding it.