The measuring time needs, and appeared the the development of agriculture. Farmers used in time, to determine the best planting period and the original lunar calendar.
The development of the egyptians tell calendar and clock time and a means of the first man. About 2800 BC, they set up a 365 day's calendar, according to their views and bright stars, such as Sirius and the Nile, the periodic rising flood on agriculture of Settings. By 2100 BC the egyptians invented a method, divided into 24 hours a day. Around the same time, their first sundial, or shadow clocks and watches, the time of day to measure. A sundial said of the time of day, by the light of the sun into the shadow of the object in some of the position.
By 1500 B.C. the egyptians invention, the more accurately tell time water clock or LouHu, it USES stable water from one vessel drop water, driving mechanical device, says hours, way.
Babylon astronomers fine-tune the LouHu, considering the distance between the earth and the sun caused by different time equation, because it's in a oval track mobile. Due to this effect, may be as much as a half hour at noon time, when the sun is highest in the sky before and after.
About 270 BC the Ctesibios design engineers Alexander water clock, rang the bell, mobile puppet, cause mechanical birds sing. The development of mechanical timepieces, until nearly 3000 years, is still in use water clock.
However, a very short period of time interval measurement is possible the hourglass. Search accurate clock started the bud of the late medieval business and the scientific revolution of the first batch of results. This needs to measure time simple pendulum weighted mechanical clocks. But these are not portable.
The first watch
In the era of the portable watches and clocks in the invention of the spring and grab the mechanism. Capture the system is a kind of mechanism, control and limit watch the same score a storehouse, conversion, otherwise will open into a control and regular energy release, a simple. The system is linked together by the capture of the gear in a simple way to "drive" and "free" condition, each cycle in the end, suddenly lock switch between. The mission also out of the same causes of mechanical watches tick noise characteristics.
Another kind of mechanical method, is regulating mechanism. Along with the regulating tiffany-twisted (also called kind)-these form a simple harmonic oscillator, control ways similar to a pendulum clocks are the pendulum of the movement of the gear system watch. This is possible because of inertia moment of regulating is fixed, as a whole wheel provides a called during the exercise regularly. These watches the ticking of produce.
Pure mechanical watches are still popular. Pure mechanical watches process high-level, accounting for their attractive. Compared to the electronic movement, mechanical watches are not accurate, usually the error of the second day. They are often sensitive position and temperature, they are the production cost, they need regular maintenance and adjustment, they are more likely to malfunction.
In the s made further accuracy tuning fork watch, it in a precise frequency tuning fork (usually 360 hz) to drive the mechanical watches. Due to the fork is a typical balance wheel place use, these watches ticks natural, not hum. Mechanical and electrical changes a tuning fork. The rotary motion converted into electronic pulse vibration task is through fork two little gems fingers called JiZhao, one of which is connected to a tuning fork of teeth. Fork vibration, JiZhao is a tiny index ratchet wheel. The index wheel has more than 300 faintly visible teeth and rotating each year more than 380000 times. Tiny drive electric coil a tuning fork 8000 turns insulation wire, 0.015 mm in diameter and length of 90 meters. This amazing feat of engineering in the 1950 s and 60 s prototype.
In the 1969 years electronic quartz watch market
The biggest black moselle in 1948, used in electronic equipment, transistor created the first electronic watches. This development become and use quartz crystal, quartz watch, it USES a small quartz crystal of piezoelectric effect, mainly is electronic sports to provide stability when the baseband to outdated: crystal formation quartz oscillators, and highly specific in resonance frequency of stability, and can be used for accurate timing mechanism pace. These main is electronic movement, all in order to promote the dial of the manipulator. Quartz movement mechanical movement ten times better.
Further development, launched the following types of watch:
Manual watch
Spring in manual watch must fall with regular users BiaoGuan rotation.
Automatic bent or automatic watch
Automatic bent or automatic mechanism is a fall in the body of the natural movement of the main dynamic mechanical motion.
Dynamic power supply or automatic quartz
Also adopted the some electronic watches watch the wearer of a sport. Dynamic power supply of quartz watch, make the wearer of a rotating arm of weight, and become a generator power supply, charging rechargeable batteries running watch bill. This concept is self winding spring sports similar, in addition to electricity mechanical spring of tension, and not produce.
1957 years of battery power supply of the watch
Electronic watch needs power as a power source. Some mechanical and electronic machinery hybrid sports also need to power. Generally provides a replaceable battery power. Watch battery (strictly speaking cells) are designed for their purpose. They are very small, and provide a small electric power for a long time (a few years or longer). The environment friendly mercury battery, made room for the silver oxide battery and lithium batteries. Cheap battery may be alkaline batteries, the size of the silver oxide is same, but life is short. In some solar watch use rechargeable batteries.
Light kinetic energy watch
Some electronic watches are using the light. A dial of photovoltaic cells on the light conversion electric power, this is use rechargeable battery. Battery watch machine core, attracted from its power. As long as the watch is often exposure to strong light (such as the sun), it never the battery needs to be replaced, and some models only for a few minutes of sunshine provide energy weeks.
The early 1970 s watch some of the solar energy has innovation and unique design, in order to adapt to the need of their power (Nepro, Sicura and some Cristalonic, aerba, seiko and xi tiecheng breathes out what type) of the solar array. Due to the progress of the decades, and improve the efficiency of solar cells decreases, and the movement and the display of power supply requirements, solar watch begin to design, looks like other traditional watch.
Radio control movement
Some electronic quartz watch can and external source synchronous time. These sources include radio time signal by atomic clocks, time signal, GPS navigation satellite, Germany DCF77 signal in Europe, the United States WWVB and other direct drive. These watches are all free run most of the time, but regular adjust to automatically select external time source, usually once a day.
Because these watches are made by external time source of very high precision adjustment, they never shut down more than the second day (depending on their quartz movement quality) of a small part, as long as they can receive external time they expect signal. In addition, their long-term precision and external time receiving signal, which in most cases (such as the GPS signal based on atomic clocks and special radio transmission time) is a 30000 years ago in the second. For all practical purposes, so, wireless remote control to keep watch nearly perfect time.
This type of change is not only the time of day, but also date, this year's leap year position, and the current daylight savings time (or close) state synchronization. They have all the information they received from external signal. Because of the continuing to be automatic update, they no longer need to manually set or reset.
Radio control movement a defect is, if radio reception conditions poor, they can't sync. However, even in this case, they will simply run, as a common quartz watch the same precision autonomous, until their future can synchronization.
Watch show
In the seventy s development with two types of display.
Model shows that
After installation, one of the digital dial at least a rotating clockwise and long, minute, rotate. Many watch with the current minutes, showing the current second third hand. Driven by quartz watch the second hand, catch to the next second mark. The mechanical machine core watch has "a second hand" never give smooth when) the whole logo movement produced name, hand just in smaller steps move and normally second, corresponding patrol 1/6 balance wheel. Hand usually machinery, the body rotation on the dial, although there are a few watch already and "hand", is by the LCD monitor simulation produce.
Digital display
Figures show that just shows for a number of time, for example, morning now, not a short needles pointing to 12 and long hand, at no. 8 on the dial.
Replace the LED display (LCD), it USES less battery power, and display will always be visible and no need to see time being pushed a button, use more convenient.
Since the 1980 s, in a digital watch technology much improved. An annual increase of new functions.