Piezoelectric Effect

In the world of physics, studying analogies between laws of electrostatics and mechanics is fascinating and they point to a very basic understanding of this Universe, and there is a deeper science behind the mysterious order of this Universe. Piezoelectric effect is yet another phenomena that describes a beautiful analogy between stress or mechanical strain and electrical voltage.

What is Piezoelectric Effect?

It was owing to the efforts of Jacques Curie and Pierre Curie, in 1880 that the concept of piezoelectricity came into existence. These physicists discovered that there are certain crystals that become electrically polarized when stress or mechanical strain is applied on them. So all elements of mechanics like stress, strain, compression and elongation can produce voltages in some specific crystals. It was established by Jacques and Pierre that when mechanical force was applied upon crystals like tourmaline, topaz, quartz, Rochelle salt and cane sugar, it led to the production of alternate electric charges on its opposite faces and subsequently it could be used to generate electrical voltage.

The crystals that showed the presence of this phenomenon were named as piezoelectric materials or crystals. So, when stress is applied on a piezoelectric crystal, it will lead to voltage generation across its surface. These crystals can be best understood as capacitors with some voltage applied on them. The voltage generated is certainly not very large, but it can be amplified to great extent by using amplifiers.

The reverse piezoelectric effect was also found to be true in researches during the later years, after the discovery of piezoelectric phenomena. As per the reverse effect, when external voltage is applied on piezoelectric crystals, they will show variance in shape and size, up to a very small extent. The electricity that is produced in the process of piezoelectric effect is known as piezoelectric.

Applications of Piezoelectric Effect

It becomes fairly easy to understand the laws of Physics once we're able to observe their applications in daily life. There are many areas where piezoelectric phenomena is used extensively. Piezoelectric effect only occurs in non conducting materials and broadly stated, piezoelectric materials are bifurcated into two groups, crystals and ceramics.

• Electric cigarette lighter uses piezoelectric phenomena for lighting the cigarette. When we press the button of an electric cigarette lighter, a spring loaded hammer strikes an in-built piezoelectric material and produces a very high voltage, thereby igniting the gas.
• Many stoves and grills come with in-built piezoelectric crystals.
• Piezoelectric transformers (quite different from conventional transformers) have become one of the most significant sources of high voltage generation.
• Piezoelectric sensors have become popular in acoustic guitars and other equipment. Variations in pressure, in the form of sound, is easily detected by using piezoelectric sensors.
• In ultrasonic transducers (used for medical imaging), the concept of piezoelectric effect is used.
• Piezoelectric crystals are also used in detection and generation of sound waves.
• Sonochemistry, industrial processing and several branches of engineering physics use piezoelectric crystals.
• In actuators, piezoelectric ceramics are used as the width and electricity produced by these crystals can be very accurately measured.
• Loudspeakers, piezoelectric motors, ink jet printers are some other devices where this effect is used.
• In microscopes, especially the atomic force microscopes and scanning tunneling microscopes, the phenomena of piezoelectric effect is used.

The above applications are just a glimpse of the piezoelectric effect. This phenomenon is observed even in bones, DNA and other biological matter inherently have the ability to accumulate charges! As studies in electromagnetism and mechanics are becoming more advanced, several other fields that employ piezoelectric effect are developing rapidly.