Piezoelectricity

Piezoelectric Materials

When a piece of piezoelectric material is mechanically deformed, a current will flow and charge its faces. and vice versa, it will be deformed when exerted to an electrical field.

$$Q=d\times F$$

Here:

• $Q$ - charge stored
• $d$ - charge sensitivity (a material property)
• $F$ - applied force

$$C=\epsilon\frac{A}{t} \implies V=\frac{d}{\epsilon}\sigma t$$

Here:

• $V$ - applied voltage
• $d$ - charge sensitivity
• $\epsilon$ - permittivity
• $\sigma$ - applied stress
• $t$ - thickness

Uses

• Converting mechanical stresses into electrical signals
• Producing ultrasonic sounds
• Producing X-rays
• Converting sounds to electrical signals
• In nano-precision actuators

Piezoelectric Transducer

Can be used to measure changes in pressure, force, acceleration, strain by converting them into an electrical signal. The applied force (or pressure) to piezoelectric crystal would generate a voltage.