Why is quartz used in piezoelectric transducer?
Quartz is used in piezoelectric transducers because of potential for high voltage input and acoustic power. Quartz is a piezoelectric crystal and when it is mechanically strained or deformed by stress, electric charges appear on some surfaces. When the strain is reversed, the polarity of the charges reverse. This allows vibration of quartz crystals to be transformed into electric pulses.
Yes, all quartz has piezoelectric properties, whether it has been tumbled or not. However, in natural quartz, were optical twinning (equally distributed left and right quartz forms inside the material) is very common, the piezoelectric effect is not strong. That is the main reason why only synthetic quartz is being used by manufacturers, where twinning is almost absent.
Quartz is used in the making of sandpaper, optics, glass, liquid filters, circuit boards, computer components, cement , mortar, and jewelry. Quartz crystals are also piezoelectric meaning when an electrical current passes through them they vibrate a small amount. Time can be measured from the vibrations of the quartz crystals so quartz crystals are often used in clocks.
The vast majority of devices that use piezoelectric crystals (piezoelectric buzzers, fish finders, atomic force microscopes, etc.) use crystals of lead zirconate titanate (PZT). The crystal oscillator in a computer or digital clock uses the piezoelectric effect, but it is usually made of pure quartz (silicon dioxide). Many different crystals and other materials exhibit the piezoelectric effect, including quartz crystals, cane sugar, and bone.
this is not how they are made naturally but how they are made for diagnostic uses: ultrasound waves are made by applying a current that is similar to the natural frequency of the piezoelectric quartz crystal, when this is applied to the crystal they produce ultrasonic waves! ADDED: As a point of detail, quartz is rarely if ever used now, replaced by much more sensitive, artificial, piezoelectric ceramics.
The question here has been framed wrongly. There is nothing like a general circuit for a transducer. Depending on a transducer you may have many circuits. For eg. a Piezoelectric crystal is a transducer, it can convert both ways; mechanical vibrations to electrical and electrical to mechanical. So you see, there is nothing like a general circuit for a transducer. Another better example would include an Antenna which converts electro-magnetic waves into a electric signal…
The simplest form of transducer from an electric signal to sound waves is by way of a small electro-dynamic transducer - really a tiny loudspeaker. But of course any transducer between these energy types can be used. Piezoelectric, capacitance, and so on. Your doctor's stethoscope does not have magnetic earpieces, nor do the earpieces used to communicate with the patient in CT or MRI scans. In the latter case, the metal would seriously interfere with…