Stopwatch countdown timer

Stopwatch (or watch) is an instrument for measuring time. (Usually, the timing intervals less than a day - otherwise the calendar.) Watches that are used for technical purposes, or with extremely high accuracy is sometimes referred to as the chronometer. stopwatch in its most common modern form (in use since the 14th century) the hour (hours), minutes, and seconds and sometimes within 12 or 24 hours.

Replica of ancient Chinese watch with incense sticks
Stopwatch History
A watch is one of the oldest human inventions. In general, it is necessary to know the basic physical processes that recur with some frequency, and a way to measure how long the process takes. As the seasons and the phases of the moon can be used to measure the runoff of certain long periods of time, so the shorter period can be used to measure the hours and minutes. Sundial, which measures the time of day using the directional shadows cast by the object illuminated by the sun, was well known in ancient times. The lamp and incense sticks burning predictable speeds have also been used as stopwatchs. Sand stopwatchs measure the passage of time, fine sand through the narrow opening in the glass container.

Historian Vitruvius reports that the ancient Egyptians used a clepsydra, timing mechanism that runs on water. Historians disagree on the origin of "Antikythera Mechanism" (stopwatchwork found near the Greek island of Antikythera, which is believed to originate from 87th p. N. E.) But it is thought that it was an early mechanical stopwatch. To 9 Ages p. n. email. Mechanical stopwatchs did not have lifts. There is a note that the 1176th Sens Cathedral installed in "Orologi" (words of grkih choir, stopwatch, and legein, speak) - a word that is still used in France for large watches. This word has led scientists to they generate these stopwatchs on the towers did not have hands and dials, but they are "talking" during the acoustic signals such as bells.

The first fairly accurate stopwatchs are stopwatchs on the towers of the 13th century made the monks in Northern Italy (and perhaps they were created). Have been used to publish the "canonical hours" in the intervals between prayer. "Canonical watches" are distinguished by the length of time, and we changed with the changes of sunrise and sunset.

It is believed that the first watch with sound obrojavanjem hours invented Jeong Chang-Sil, the chief engineer of Korea, during the king Džoseona. Dubbed the Chagyongru, which in Korean means "the countdown stopwatch."

The earliest table stopwatchs that survive today as watches from the mid 16 century from metallurgical cities of Nuremberg and Augsburg. These stopwatch had only one hand. Hour meter was divided into four equal parts, so that the stopwatch could tell the time by 15 minutes.
The stopwatch on the Big Ben, London, England. A person 5 feet tall and 4 inches (1.63 m), which shows the label for 6 hours was placed in a life-size image. Hands for long hours of 9 feet (2.7 m) and the minute hand 14 feet (4.3 m)

The next significant development in accuracy occurred in the 1657th with the invention of the pendulum stopwatch. Even before Galileo had the idea to use a pendulum to start flews stopwatchwork. Christiaan Huygens, however, is usually considered to be the inventor. He made a mathematical formula of the length of the pendulum and time (99.38 cm or 39.13 inches for the one second time) and gave the first such watch made. English watchmaker William Clement 1670th made a "funicular railway with an anchor," as opposed to Hajgensovog "lift the crown." In less than a generation have been added, and the minute hand and second.

The excitement for hours with a pendulum attracted the attention of designers who have made various forms of watches. Made the case for placing the pendulum stopwatch. English watchmaker William Clement invented this case the 1670th About the same time the body began to made of wood with a face of glass enamel. Eli Terry's 17th November 1797th patented the first hour. He is known as the founder of the American watch industry.

The development of electronics in the 20th century led to stopwatchs with no stopwatchwork. Time on these online stopwatch is measured in various ways, for example by means of quartz crystal or decay of radioactive elements. Even mechanical stopwatchs powered batteries, which is a winding stopwatch was made redundant.
Types

Stopwatchs can be classified by the manner in which displays the time and in the way they measure time.
The division according to the stopwatch showing time
Analog stopwatchs