stopwatch - a tool that is used to specify, maintain and coordinate time. Mechanical clock, which uses weight-lifting and energy source, traditionally known as the chronometer. In general terms, today the word "hours" means any device for measuring and displaying the time.
The stopwatch is one of the oldest human inventions, as human activity over time required measurements over short periods of time than the standard unit, such as day, month and year. Devices operating on several different physical principles, have been used for thousands of years and have resulted in the creation of devices known today.
A online timer tool is an instrument for measuring and indicating the passage of time.Used since antiquity, but the accuracy of their measurements has increased dramatically in the last century.
The clock is one of the oldest inventions of mankind, the need arose to measure intervals of time shorter than the natural units, ie, the day the lunar month and year. As has been evolving science and technology manufacturing, new models have emerged with greater accuracy and lower cost of manufacture.
Classification by purpose
Knowing the current time (wrist stopwatch (automatic or 'string'), pocket stopwatch, stopwatch hall or wall) Measure the duration of an event (chronograph, stopstopwatch, hourglass) Setting the hour sounds like bells or whistles (pendulum clock, wriststopwatch to beep every hour) Activate an alarm in a specific time (clock)
Timebase
The type of time base used is usually not important to name the type of clock. The most common are:
Pattern network. No oscillator and uses as reference the 50 Hz (or 60 Hz) network. Issuing pattern. The time base would become some kind of PLL, stuck with some of the stations time. stopwatch fingerboard. The oscillator is controlled by a pitch in the interleaving feedback loop. Quartz stopwatch. Replace a tuning fork quartz resonator, usually to 32768 Hz. Atomic clock. It is based on even in the feedback loop with a cavity molecules susbtància appropriate so excited resonance of one of its atoms.
Operation of online stopwatch An electronic clock is a clock in which time base is electronic or electromechanical, like frequency division. Accuracy of the clock depends on the time base, which may consist of an oscillation or an adapter that as a reference, generates a periodic signal.
The frequency divider circuit is a digital format by a series of counters to obtain a frequency of 1 Hz, which lets you display seconds. If you want to display decimals, division stops at up to 10 Hz. This often happens in the presentation module, which can be electronic or mechanical in nature, where other dividers to separate the seconds, minutes and hours to present them with some kind of screen.
Electronic or quartz clock that can synchronize your move when the time signal broadcast or specific radio stations, as well as (for ultra precise time) satellite GPS. Network master clock
Network master stopwatch clock system designed to provide the exact time a wide range of customers in the cities, factories, etc. It consists of one primary and several secondary clocks and communication lines.
Primary watches are designed for precise timing and its transmission to the secondary clock.
Previously represented the astronomical clock or timepiece, where instead of the shooter was electro-mechanical unit forming teams at the secondary clock, in the simplest case - provides circuit circuit every minute.
Now, with the development of electronics and telecommunications - digital clock accuracy class with multiple channels introducing amendments.
Slave clocks are used to display the time in the master clock networks.
Previously represented a gear without the engine controller and the second hand, minute hand moved from the solenoid pulses of alternating polarity voltage of 27 volts on the primary clock, the hour - through gear 1:12 [source not specified 819 days].
Now - cheap independent quartz watches with a clock from the primary may also directly by radio signals exact time, in some cases - GPS.
Stopwatch clocks - small stopwatch clock simplified device with weights- a variant of mechanical pendulum stopwatch clocks, anchor escapement and free weights as a motor. As the pendulum in some models use two "feet" moving in protivohod each other. Variation occurs with the battle (another chain with removable weights for combat, which can optionally be removed from the chain and hang next to a special hook - so-called "mode without a fight").
Cuckoo stopwatch clocks - wall stopwatch clocks in an elegant building, most mechanical watches (stopwatch clocks) to fight simulating singing cuckoo. Usually sounds (one to twelve) are heard every hour, counting the current time, and often interspersed gong ("Boom - Cuckoo"). Mechanism imitates a cuckoo, developed in the mid XVIII century, and since then has remained almost unchanged. Homeland cuckoo stopwatch clock is located in the heart of the Black Forest German town of Triberg, at least, that there is a museum of cuckoo stopwatch clocks. Quartz stopwatch clock
Kind of electro-mechanical stopwatch clock. It is based on the piezoelectric effect, the property of quartz crystals, for example, deformed under the influence of an external electric field, and polarized by mechanical deformation. The crystal quartz, having a small size, can be a much more stable to generate fluctuations with high temporal and thermal stability. The mechanism consists of a quartz watch battery, electronic generator, counter divider and the output stage of the amplifier, which is loaded on the coil synchronous motor, which, through a system of gears drives the stopwatch clock. Digital Watch Main article: Digital stopwatch clock The stopwatch clock on the PDA Electronic stopwatch clocks Desktop Alarm stopwatch clock Modern digital stopwatch clock with calendar and thermometer
Watch, based in the oscillation periods of the master oscillator with electronic circuits and displays the information on a digital display.
The first digital watches were made in separate tubes and then transistors and microchips.
First wrist digital watch has an LED display, but they can tell the time is very short: too greedy proved LEDs. Then used the properties of liquid crystals oriented in the electric field and to transmit light from one polarization direction. When placed between two polarizers, the light from an external source does absorbing system polarizer, liquid crystal polarizer, reflector under electrical field becomes dark and forms a picture element. This has resulted in significantly reduced power consumption and replacement of batteries is much less common.
In modern digital stopwatch clock built in, usually a specialized microcontroller, and have had many hours of service functions (alarms, ringtones, calendars, etc.), but the microcontroller also continues to consider the oscillation periods of the same quartz crystal. Note: There are also electronic stopwatch clock, based on the principle of counting periods Frequency, many countries have very strict requirements for frequency stability, but also the oscillation frequency of the network load can be varied, and the accuracy of these hours can not be considered normal, although for many people, it is sufficient.
Kind of electronic stopwatch clocks that display the time in binary code, called a "binary stopwatch clock" (English Binary watch). To display bits are commonly used LEDs. The number of groups of LEDs can be different, they may differ in size and location. Part of LEDs shows the hours, the other - minutes. LEDs may be responsible for counting seconds, date, etc.
In any mechanical stopwatches need to distinguish four major parts:
engine (spring or weight)
the transmission gear
regulator conditioning fluidity
distributor or down, on the one hand, the pulses are transmitted from the motor controller are necessary to maintain the oscillation of the latter, and, on the other hand, subordinates move the gearbox, and therefore the action of the motor patterns of vibration control.
Meter time in the narrower sense is the regulator. Gears, sealed with arrows dial - counter-measured units of time control. Recognizing the daily rotation of the earth on its axis is strictly uniform, we are in it, we have only to compare the scale intervals or time units. Usually the unit of time are seconds, 1/86400 of the day. On a different track of time, the star, middle, true day - see the time.
Regulators stopwatch movements are arranged so that they measured out the time intervals equal to the whole or a second, or a half, a quarter or a fifth of a second. If for some reason the controller will measure shorter time intervals, the counter will show more of them in this time period. In this case, the clock, as they say, go ahead. If the interval is longer than the specified control - clock is slow. Agreeing on the initial moment of the day, in other words, about the moment when the hour meter must read zero elapsed time units arrive at the concept of Amendment hours. It is positive if the clock backward, negative - if left on. Changing the clock correction for a certain period of time is called the course hours (eg, daily, weekly, hour course). Progress is positive if the clock is slow, negative, if the clock goes forward. Progress expresses precisely measured out the evasion control periods from the accepted one. The amendment is the conditioned hours and, in addition, at any time by simply moving the minute hand counter correction clock can be made less than one minute.
Dignity of the same hours is small, and most importantly - constant speed. Stroke of good astronomical clocks and chronometers should preferably be independent of changes in temperature, pressure, humidity, random shocks, abrasion axis mechanism, thickening of lubricating oil, the molecular changes in different parts of the mechanism, etc. Astronomical Clock is divided into two main types:
'Permanent', in which the driving force is the weight of weights and pendulum control
"Portable" where the movement is produced by the elastic force is gradually unfolding spring, and adjustable elastic vibrations, thin spiral connected to the so-called. balance (see below).
First timers are called in astronomy "clock" in the narrow sense of the word, or "pendulum". They are located at the observatories at constant astronomical instruments (see Practical Astronomy), mounted on stone pillars, or in the wall clocks are often placed in the basement of the observatory, in order to protect against possible changes in temperature ("normal" hours.) Cellar visit only for winding hours, as even the heat of the body can affect their progress. Reading the same hours, that is, the "hits" of the pendulum (always second), compared with other clocks with a microphone installed in the basement and connected to the phone (the phrase, although generally accepted, but it is not true. Blows "ticking" makes no pendulum ( controller), and the mechanism of descent). With proper installation and care of "permanent" astronomical clock should have daily rate of 0.3 s, and its daily changes should not exceed one-hundredth of a second.
Timers of the second type are called chronometers. Distinguish between "table" or box-chronometers (size of about 1 ½ -2 Decima. Diameter, 1 Decima, height, a simple swing the balance lasts ½ seconds), and pocket chronometers (the size of a well-known, commonly so-called. Chetyredesyatniki, ie complete Double Vibrations lasts 0.4 seconds, a simple swing - 1/5 seconds). Quality pocket chronometers on average sensitivity as table below. Chronometers are in determining geographic locations of places, the work portable astronomical instruments (see Practical Astronomy), in determining the time and longitude at sea, etc. Dining chronometers for ships are placed on weight gain of Cardan. Constant stopwatch ("pendulum") almost exclusively, and chronometers in most cases governed by the stellar second time - the so-called. "Star" stopwatches and chronometers. Less likely to use "average" online chronometer (ie reaching the average time). Choice is due to the convenience of observation or treatment for those or other problems in astronomy.
In stopwatches and chronometers are still certain astronomers are appreciated, but not sharp, and without unnecessary noise hits ("ticks"). As the best masters of astronomical clock or chronometer to be named Kesselsa, Peel, Dent, Thiede, Hovyu (Howüh), Knobliha, Frodshema, Nardena. Creators of the "highest" stopwatchmaking and movement: Peter Leroy (born Pierre Le Roy), John Harrison, George Graham (born George Graham), Dyutertr, John Arnold (born John Arnold), Ferdinand Berthoud (born Ferdinand Berthoud ) Juergensen.
