The stopwatch tool

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.