Piezoelectric Effect

wikipedia article

What is it?

The piezoelectric effect is the ability of some materials to produce electric current when they are exposed to physical stress. It also works in the opposite way, with the material deforming slightly when a small electric current is applied. Piezoelectricity was discovered more than one hundred years ago and has applications in electronic clocks, gas ovens, inkjet printers, and many other appliances.

History

The piezoelectric effect was first discovered in 1880 by brothers Pierre Curie and Jacques Curie. The Curie brothers only found that piezoelectric materials can produce electricity. The next development was the discovery by Gabriel Lippmann that electricity can deform piezoelectric materials. It was not until the early twentieth century that practical devices began to appear. Today, it is known that many materials such as quartz, topaz, cane sugar, Rochelle salt, and bone have this effect.

How the Piezoelectric Effect Works

The piezoelectric effect occurs when the charge balance within the crystal lattice of a material is disturbed. When there is no applied stress on the material, the positive and negative charges are evenly distributed so there is no potential difference. When the lattice is changed slightly, the charge imbalance creates a potential difference, often as high as several thousand volts. However, the current is extremely small and only causes a small electric shock. The converse piezoelectric effect occurs when the electrostatic field created by an electrical current causes the atoms in the material to move slightly.

Applications to ham radio

Quartz has a natural frequency that is ideal for creating the oscillations needed to maintain exact frequency or time. Hence Quartz is very useful in the construction of high stability oscillators

Electronic Theory
Physical quantities	Current * Gain * Impedance * Power * Q of a circuit * Radiated Power Measurement * Reactance* Resistivity * Resonance * Voltage
Components	Baluns * Bipolar-Junction Transistors * Capacitors * Diodes * Inductors* Lasers * Microphones * Resistors * Transformers * Wire
Circuits	Attenuators * Digital Signal Processing (DSP) * Dummy load * Filters * LC filters * Power Supply Design * Rectifier Circuits
Design	Amplifier Design * Oscillator Design
Electromagnetic Waves	Relative power (Decibels) * Harmonics * Interference and BPL