Quartz clock
A quartz watch is an electro- mechanical or fully electronic clock, the clock is an electronic quartz oscillator whose frequency is maintained by means of a quartz crystal. Quartz without direct display, which are usually installed in a computer system are referred to as real-time clock.
- 4.1 Overview
- 4.2 milestones
- 5.1 Literature
- 5.2 documents
- 5.3 External links
Physical and technical background
The quartz watch is based on the physical realization that an increase in the frequency of the clock (usually the balance of mechanical clocks) enables a more accurate time measurement, which led to the development of so-called Quick Schwinger- riots for example. First attempts to use a clock with a frequency that was higher than that of a balance, were the so-called tuning fork watches with frequencies of 100 Hz and sizes by five centimeters.
The centerpiece is a watch crystal in the form of a quartz tuning fork for typically 32,768 Hz, from which by means of frequency division by 215 -. Serve a total of 15 flip-flops - can be derived second pulses Since quartz is very hard, is excitation of the crystal thickness vibrator as the resonant frequency of a crystal block of a few millimeters in size that would fit easily into a conventional watch case, much too high, namely in the megahertz range. By tuning fork shape the quartz was easier to bend, and the size would be smaller, so that a quartz fit despite deep resonant frequency in a watch case. Quartz tuning fork in shape, however, are difficult to manufacture and expensive. Rod-shaped flexural oscillators are even smaller and also are easier and cheaper to produce. Therefore, small crystals using low frequency usually rod-shaped bending vibrator. This frequency is a compromise, because the power consumption of the flip-flops increases proportionally with the frequency and is intended to provide some annual power the battery of the clock.
At the beginning we used special Zählröhren for the frequency divider, since the 1950s, digital counter circuits ( flip-flops ) in integrated circuits based on transistors to divide down the frequency of the crystal oscillator to a second.
These oscillations drive either a Lavet stepper motor, synchronous motor or electrical balance chair a mechanical movement or give the clock for an electronics before. The display can be realized by mechanical hands, Liquid Crystal Display ( LCD) or light emitting diode ( LED).
Construction
Fundamental
The main components are a quartz clock, a clock on the basis of quartz oscillations, electronics for processing the pulses, and the user inputs, a display section for displaying time information and, if operating conditions of the clock and a power supply.
The energy source is used instead of a driven by weights or spring mechanical pendulum or balance wheel used:
- The power grid (for larger watches )
- A mobile power supply such as battery or battery (usually a AA or button cell)
- A high-capacity double-layer capacitor charging by a flywheel generator (similar to the lift mechanism for automatic watches ) or
- A capacitor which is charged by a mounted generally at or below the dial solar cell.
"Complications "
Quartz watches can - just like mechanical watches - have different complications. Examples of complex quartz movements for watches are:
- The caliber 6870 Citizen of six-hand, date, and with four push buttons in addition to the crown, in which a chronograph, a perpetual calendar, two alarms, down timer and a second time zone are realized. Most pointers have multiple uses; the currently active mode is displayed on its own pointer with positions such as TIME, ALM, etc. CHR.
- The Jaeger-LeCoultre Calibre 633 ( since 1987) with 233 components and 27 jewels has time and date display, alarm clock and mechanical chronographs. This caliber has been used for example in the IWC Ingenieur Chrono Alarm.
- The caliber ETA 1066, used exclusively in the Omega Speedmaster X -33 ( 1998 ), has in addition to three hands for hour, minute and second a located around the central axis circular LC Display Field ( " Hybriduhr " ), also with circularly arranged ads for various functions such as perpetual calendar, countdown timer, chronograph, second time zone (24 -hour display ) and two alarm functions.
- Similar caliber with pointers and LC displays, there are also other providers, such as Breitling and Victorinox.
- Tissot offers hybrid watches under the name " T-Touch " to where the functions are selected by touching the watch at various points.
- The caliber 6770 the Japanese company is a Shellman Grande Complication Chronograph, Perpetual Calendar Rattrapante and repetition. It is based on a Citizen Calibre.
- The Timex caliber 730 has flyback hand.
Accuracy
Quartz watches with a watch crystal with the normal vibration frequency of 32,768 ( = 215) Hz usually have a Uhrgang ( progressive deviation ) of ± 10-30 seconds a month. Because of these errors cumulatively, a quartz clock must be synchronized more frequently, ie be set to the value of an accurate clock or a time signal transmitter.
Gait deviations of a quartz watch can be minimized by:
- A constant temperature as possible
- Temperature compensation (measurement of the crystal temperature compensation and a knowledge of the temperature coefficients)
- Manual change ( via control button) the divider ratio of the electronic frequency divider according to the individual user conditions (climate, supporting custom day / night, etc ),
- Operating the quartz crystal in a quartz furnace (OCXO ), a form of the thermostat, which keeps the temperature constant,
- Connection to radio controlled watches, which are regularly synchronized by radio ( in Central Europe receiving the DCF77 time or HBG ) with the Coordinated Universal Time, or
- Access to accurate clocks via USB, Bluetooth or the Internet and synchronization with more accurate clocks. Many portable devices are synchronized when connected to the PC to the PC time, PCs turn can be synchronized via NTP with Internet time servers.
History
Survey
The first quartz watch was developed in 1919 by HM Dadourian based on ultrasonic experiments with quartz crystal by Paul Langevin 1918 This first prototype showed, however, -. Well as the 1929 developed by the Canadian telecommunications engineer Warren Alvin Marrison at Bell in the United States - because of insufficient temperature compensation to poorer results than the transition at this time nor conventional mechanical precision pendulum clocks.
Only the quartz watch of Adolf Scheibe and Udo Adelsberger achieved significantly better results gear. The miniaturization of electronics led in 1970 to the first digital stopwatches and quartz wristwatches.