online timer, online stopwatch
Water clocks, also known as the water clocks, may be the oldest time-measuring instruments independent of astronomy. We do not know when they were invented. The bowl-shaped outflow is the simplest form of a water clock and is known to have existed in Babylon and in Egypt around the sixteenth century BC. BC. Other regions of the world, such as India and China, also have evidence of very ancient water clocks, but the dates are less certain. Some authors, however, indicate that water clocks appeared as early as 4000 BC in these regions of the world.
The Greeks and Romans have advanced the online timer design of water clocks by adding complex gear systems, allowing to connect to PLCs original but resulted in greater accuracy. These advances were amplified and transmitted to Europe through Byzantium and Islamic civilization. Independently, the Chinese developed their own advanced water clocks (钟) in 725 AD, and reported their findings to Korea and Japan. In addition, some models of hourglasses were developed independently and finally a number of techniques have been passed by the great trade routes (the Silk Road, trade ...).
In 797 (or possibly 801), the caliph of Baghdad, Harun al-Rashid, gave Charlemagne a white elephant of Asia named Abul-Abbas and a clepsydra iconic technological know-how of Arab civilization.
In the thirteenth century, Al-Jazari, an engineer who worked for the king of Diyar-Bakr, Nasir al-Din, made numerous clocks of all shapes and sizes. His book describes fifty mechanical devices in six categories, including water clocks. The most famous clocks include the elephant, the Scribe and the clock of the castle, which were all rebuilt successfully. In addition to telling the time, these clocks were important symbols of grandeur and wealth of the state Urtuq.
Candles and hourglasses
Main article: clock fire.
Clepsydras are rather imprecise measure the time due to the smooth flow of liquid. And other more specific instruments are used.
The clock light is used in the Middle Ages: candles and incense sticks burning at relatively predictable, are used to estimate the passing of time, and then give way to oil lamps in use in the eighteenth and nineteenth centuries in the West.
In an hourglass whose use is mentioned mainly in the West of the eighth to fourteenth centuries (from the second century an instrument similar to an hourglass, but containing oil is employé2) especially in marins3 or to measure short times (lesson university sermon), a quantity of fine sand pours through a tiny hole at a constant online stopwatch rate and indicates the transition from a period of time. The hourglasses did not contain a regular sand, but a mixture of marble powder calcined, pulverized egg shells and lead or zinc1.
In the Middle Ages, time and social life are especially punctuated by the ringing of bells (each tone lasting 1/4h 1/2h or) that appear likely in the fifth or sixth centuries in the towers, marking the various canonical hours. From the eleventh century, free communes are raising belfries whose bells mark the time not religious but civil4 time.
Old mechanical clocks
None of the first mechanical clocks survived from the thirteenth century in Europe, but several mentions in church records reveal some of the first clock time.
Horologia word (Greek ὡρα, time and λέγειν, say) was used to describe all these devices, but the use of this word for all measurement tools of the time we hide the true nature of their mechanisms. For example, there is a document describing the installation in 1176 of a "clock" in the cathedral of Sens, but the mechanism used is Unknown5. According to Jocelin of Brakelond in 1198 during a fire at the abbey of St Edmundsbury, monks ran the clock to fetch water, indicating that their water clock had a reservoir large enough to help extinguish occasional fire.
A mercury clock described in the Libros del Saber Astronomía, a work written in the year 1277 by King Alfonso X of Castile says Sage consisting of translations and paraphrases of Arabic works, is sometimes quoted as evidence Muslim knowledge of a mechanical clock. The first mercury engine robots was invented by Ibn al-Khalafa Muradi.