Countdown timer history

The first countdown timer were (if it can be called so) sundials which the shadow of the pin, which moves as a result of the rotation of the earth, a measure for the time indicated. Through hourglasses and various other mechanisms eventually became the mechanical pendulum  timer. From that moment the time with any accuracy. The invention of the mechanical  timer is attributed to the Frenchman Gerbert (later Pope Sylvester II), who lived around the 10th century. Until the early modern period was a  timer the most complicated machine that one could make.

At sea, a pendulum  timer unusable. Only after the invention of the unrest could also be measured accurately as the time which the accuracy of the navigation benefited. The sun's position is indeed together with the time and position at sea.

 timers with a sling and with a restlessness in comparable accuracy. A deviation of one minute per week is possible.

Even more accurately, the use of a quartz crystal, the operation of which is based on piezo electricity, deformation as a result of an electric voltage and vice versa. A deviation of less than 1 second per week for a quartz movement feasible.

The most accurate  timers are atomic  timers, which are directly on the definition of the second based.

Besides the sundial, there are also modern  timers that keep time from an external source involved: eg radio  timers.
Time Display
Arabic dial with 3 groups pointers
File :22-digital- timer screencast. Ogg
digital  timer principle

We can also distinguish  timers to the method of time display:
An analog  timer typically has a dial 2 or 3 and driven by the  timer hands, fixed to concentric shafts which pass through the center of the dial stabbing.

The rest of the mechanism is then situated behind the dial. The order in which the pointers are, is almost always the same. The only exception is the wekwijzer that is at or below the hour hand can be located and then in a different way functions. The wekwijzer is therefore discussed separately below.

    The second hand is on top. This is usually a long, thin needle, sometimes of a different color to avoid confusion with the other hands to avoid.

There are also  timers with a short second hand on a separate, small needle plate. Older  timers often have no second hand. The second hand makes one revolution per minute (60 seconds) and sometimes the numbers 0 t / m 59 (or only the multiples of 5) along the perimeter of the dial indicated. In general, the second hand does not put the same: it is possible that the countdown minute timer hand exactly one minute while the second hand is not pointing upwards.

    Under the second hand is the minute hand, also called big hand. This is thicker than the second hand. The minute hand rotates in one hour (60 minutes) around. Are the numbers 0 / to 59 along the circumference of the dial, then apply also to the minute hand. A  timer can often be put right by manually pushing the minute hand forward. The hour hand will then drop even further, the second hand does not.

    Among the minute hand is the hour hand and minute hand. This is shorter than the minute hand and often decorated. He makes one revolution per 12 hours. While the numbers 0 t / m 59 (for the minute hand and second hand) usually lacking, are usually the numbers from 1 t / m 12 along the circumference and sometimes also the numbers of 13 t / m 23. The numbers can also dashes or other symbols. The oldest  timers have only an hour hand, because they are not very accurate and previously little one was interested in an accurate time indication.

Online stopwatch for teachers

Nowadays one can paid number 0900-8002 to select the time data to hear, that previously was 002.
Execution

A third difference is the implementation: pendulum  timers for proper operation according to an immobile arrangement and therefore as wall  timer or grandfather  timer run. Other  timers know more versions: as a watch (portable  timer), alarm etc.

On the basis of online stopwatch timer the implementation are mainly antique and art historians again a distinction based on

    the region of origin, for example, a Frisian  timer, a chair Frisian  timer, a  timer Sallander Zaanse  timer or an English lantern  timer;
    the period of manufacture which often coincides with a certain style period, for example, a Louis XVI- timer, or a  timer in Empire style;
    the figure as an ornament decorates the  timer, such as a  timer or a cuckoo  timer horses.
    The  timer in the  timer, see Pendulum ( timer)

Some  timers display once per hour, half hour or fifteen minutes a beep.
Energy

A  timer may involve energy from a mechanical or an electrical source. A mechanical source is a weight or spring. A power source batteries, batteries, mains or solar cells. Some watches use arm movements to a spring to wind or a battery to charge.
Anchor

Below the operation of the escapement gear wheel and comprising anchor. The anchor holds the pinion (ankerrad) at each tap as against, and also allows the unrest (the yellow wheel in the picture) each a little push. The anchor with a certain frequency by the turmoil and fro.


The stroke movement is a movement that in a mechanical manner by means of a percussion produces sounds that indicate what time it is at that moment. This is done by one or more blows of a hammer on a bell, a tone or tone bar spring.
On TV

 timers are also on television. An important example of such a online timer is a  timer that appears on the screen for about 5 minutes before the daytime programming, otherwise there will now first a program list before the  timer appears on the screen. Of the three Dutch public broadcasters use only Netherlands Netherlands 1 and 2 still such  timers (Netherlands 3 not since 2000).

Throughout the seventies and early eighties were analog  timers used. In the course of 1984, the first digital  timers on the screen that can be simulated with computers, which were used until 15 March 2010. The analog  timer after 1984 was also occasionally used until about 1993. One of these analog  timers can be seen in the picture and sound Experience. The exhibition of this museum is a device that could be switched between  timer and title cards or idents. The institute has also held other  timers, but these are not part of the exhibition.

Countdown timer free

A digital  timer shows the hours and minutes, and sometimes seconds as numbers again. The hours are as the numbers from 0/23 to be displayed, or if the numbers 1/12 following the analog  timer, but with the addition AM (Ante Meridiem) for before noon or PM (Post Meridiem ) for the afternoon. Sometimes there is still an indication for the half of the day. The minutes and seconds as the numbers 0 / to 59 displayed.

The egg timer counts, after a certain time to set the time back to zero, then gives a beep and stop.

Some  timers are incorporated into appliances, for example, the VCR, the computer, the time  timer, and are not, or not only intended for direct display time but also to events at a certain time to take place or the time or duration of certain events to register. Also an oven or microwave often has a digital  timer or egg timer sort built. (All this says nothing about the suitability of the device for eggs.)
Roman numerals

Many online timer have Roman numerals on the dial. It is almost always presented as the 4 'IIII' while the modern spelling of Roman numerals "IV" prescribes. It should be noted that 'IIII' traditionally lawful. There are several theories on why a timepiece ever 'IIII' writes, for example, because the first letters of the name of Jupiter (IVPITER) or because they want to avoid on the dial as often the characters X and V to use. A famous exception is the face of Big Ben.
Rehearsal Work

There are also watches that time on command, by pressing a button, audible (see Rehearsal Work).
Telephone beep
Notification Time Machine PTT

The telephone beep looks a bit like a rehearsal work. Here, however, a time  timer that constantly speaks but who only audible to those who press the button (ie that the number of the period of notice).

The adjacent unit was from 1934 to 1969 at the Dutch PTT in use. In particular, the company laboratory of the PTT, the Dr. Neherlaboratorium, plays an important role. The device uses a rotating drum on which film strips are - just as consistent as a sound film used. The top photo shows the right 24 pages on which the hours are recorded: "0 hours", "1 hour" to "23 hours". Behind one of the strips, there is a lamp which by the strip on a light-sensitive cell appears, so that the voice is heard via the telephone. Half a revolution later (bottom photo) is the right part of the drum and close the left, we see that the minutes of "zero" to "fifty-nine." Behind one of these strips is a lamp. Every minute the lights moved to another time audible.

The film strips were voiced by Cor Hoogendam, the sister of the inventor lark. The story goes that the daughter of the inventor was present when the unit was put into service and festive they surprised shouted "That's Aunt Cor!" when she heard the voice. Since then, the telephone beep behind the scenes "Aunt Cor" called.

Online stopwatch and timer

The first  timers were (if it can be called so) sundials which the shadow of the pin, which moves as a result of the rotation of the earth, a measure for the time indicated. Through hourglasses and various other mechanisms eventually became the mechanical pendulum  timer. From that moment the time with any accuracy. The invention of the mechanical  timer is attributed to the Frenchman Gerbert (later Pope Sylvester II), who lived around the 10th century. Until the early modern period was a  timer the most complicated machine that one could make.

At sea, a pendulum online timer unusable. Only after the invention of the unrest could also be measured accurately as the time which the accuracy of the navigation benefited. The sun's position is indeed together with the time and position at sea.

 timers with a sling and with a restlessness in comparable accuracy. A deviation of one minute per week is possible.

Even more accurately, the use of a quartz crystal, the operation of which is based on piezo electricity, deformation as a result of an electric voltage and vice versa. A deviation of less than 1 second per week for a quartz movement feasible.

The most accurate  timers are atomic  timers, which are directly on the definition of the second based.

Besides the sundial, there are also modern  timers that keep time from an external source involved: eg radio  timers.
Time Display

Arabic dial with 3 groups pointers
File :22-digital- timer screencast. Ogg
digital  timer principle

We can also distinguish  timers to the method of time display:

    analog
    digital

An analog  timer typically has a dial 2 or 3 and driven by the  timer hands, fixed to concentric shafts which pass through the center of the dial stabbing. The rest of the mechanism is then situated behind the dial. The order in which the pointers are, is almost always the same. The only exception is the wekwijzer that is at or below the hour hand can be located and then in a different way functions. The wekwijzer is therefore discussed separately below.

    The second hand is on top. This is usually a long, thin needle, sometimes of a different color to avoid confusion with the other hands to avoid. There are also  timers with a short second hand on a separate, small needle plate. Older  timers often have no second hand. The second hand makes one revolution per minute (60 seconds) and sometimes the numbers 0 t / m 59 (or only the multiples of 5) along the perimeter of the dial indicated. In general, the second hand does not put the same: it is possible that the minute hand exactly one minute while the second hand is not pointing upwards.
    Under the second hand is the minute hand, also called big hand. This is thicker than the second hand. The minute hand rotates in one hour (60 minutes) around. Are the numbers 0 / to 59 along the circumference of the dial, then apply also to the minute hand. A  timer can often be put right by manually pushing the minute hand forward. The hour hand will then drop even further, the second hand does not.
    Among the minute hand is the hour hand and minute hand. This is shorter than the minute hand and often decorated. He makes one revolution per 12 hours. While the numbers 0 t / m 59 (for the minute hand and second hand) usually lacking, are usually the numbers from 1 t / m 12 along the circumference and sometimes also the numbers of 13 t / m 23. The numbers can also dashes or other symbols. The oldest  timers have only an hour hand, because they are not very accurate and previously little one was interested in an accurate time indication.

A  timer can often serve as an alarm online stopwatch and therefore has a wekwijzer which the alarm is set.

    In many wall  timers is the wekwijzer on the hour hand. He turns the hour hand and it can hand over the hour hand adjusted. State wekwijzer top, then the alarm goes off. On the hour hand, near the axis, the numbers from 1 t / m 12 engraved to be helpful when setting the alarm.
    A minor alarm has wekwijzer under the hour. This does not rotate along with the movement, but is used by the user at a desired time setting. Runs the hour hand on the wekwijzer, then the alarm goes off.

Finally, many  timers the date, month, weekday and the moon phase state. The indication of this is usually with numbers or letters behind a window.

 timers with a pendulum or unrest are usually analog.