If the amplifier were perfectly noise-free, the oscillator would not start. When the circuit is powered up, a single burst of shot noise (always present in electronic circuits) can cascade to bringing the oscillator into oscillation at the desired frequency. The output of the resonator feeds back to the input of the amplifier, and the resonator assures that the oscillator 'howls' with the exact frequency of interest. The resonator acts as an electronic filter, eliminating all but the single frequency of interest. The electronic circuit is an oscillator, an amplifier whose output passes through the quartz resonator. National Bureau of Standards) discovered that a crystal oscillator could be more accurate than a pendulum clock.

Later, scientists at National Institute of Standards and Technology (then the U.S. However, when Walter Guyton Cady found that quartz can resonate with less equipment and better temperature stability, steel resonators disappeared within a few years. In the early 20th century, radio engineers sought a precise, stable source of radio frequencies and started at first with steel resonators. Similarly, since its resonator does not change shape, a quartz clock will remain relatively accurate as the temperature changes. A quartz plate's resonance frequency, based on its size, will not significantly rise or fall. Fused quartz is often used for laboratory equipment that must not change shape along with the temperature. Quartz has a further advantage in that its size does not change much as temperature fluctuates. Quartz microphones are still available, though not common. Similar crystals are used in low-end phonograph cartridges: The movement of the stylus (needle) flexes a quartz crystal, which produces a small voltage, which is amplified and played through speakers.

Since quartz can be directly driven (to flex) by an electric signal, no additional transducer is required to use it in a resonator. In a reverse effect, if charges are placed across the crystal plane, quartz crystals will bend. However, quartz is also a piezoelectric material: that is, when a quartz crystal is subject to mechanical stress, such as bending, it accumulates electrical charge across some planes. Many materials can be formed into plates that will resonate. Bottom right: quartz crystal oscillator, left: button cell watch battery, top right: oscillator counter, digital frequency divider and driver for the stepping motor, top left: the coil of the stepper motor that powers the watch hands.Ĭhemically, quartz is a specific form of a compound called silicon dioxide.

Casio prototype