What is a timer?

Question 1: What kinds of timers are there? The types of timers include electromagnetic point timer, spark timer, continuous timer, parking timer, reaction timer, amplification timer and window timer. Electromagnetic point timer and spark point timer are the most common. Electromagnetic dot timer is a kind of timing instrument using AC power supply. Its working voltage is 4-6V, the power frequency is 50Hz, and it ticks every 0.02s The electric spark timer is a timing instrument which uses spark discharge to punch holes in paper tape and display dots. It uses 220V AC voltage, and when the frequency is 50Hz, it hits the dot every 0.02s s. When the EDM timer works, the resistance to guide the movement is relatively small, and the test error is smaller than that of the electromagnetic dot timer.

Question 2: What are the timing tools? (more)! ! ! ! ! ! ! ! ! ! ! ! ! ! ! 5-minute sundial, ghost fish, copper pot dripping, Zhang Qian leaking, Yanyou dripping, dragon boat incense leaking, dragon water, equatorial sundial, equatorial theodolite, armillary sphere, hourglass, incense burning (one foot time), fire timing, candlelight timing, water clock, eyes and biological clock (chicken).

Clock stopwatch electronic watch

Question 3: What timepieces did China have in ancient times?

Guibiao is the oldest timepiece in China. There are records about the use of Tugui in the ancient book Zhou Li, which shows that Guibiao has a long history. Standard gauges use the length of the sun's projection to judge time. It consists of two parts, one is the benchmark or stone pillar for measuring the shadow of the sun standing upright on the flat ground, which is called the table; One is a rigid plate used to measure the length of the surface shadow in the direction of due south and due north, which is called Gui. Since the shadow of the sun can be measured in units of length, it is logical to express the "yin" of time and the length of time in minutes and inches.

sundial

A sundial is also an instrument for measuring time by observing the shadow of the sun, which mainly determines the time or the number of minutes at that time according to the position of the shadow. Judging from the unearthed cultural relics, the sundial was used before the Han Dynasty, and it was always a common timer before the mechanical clock was introduced to China. The main part of a sundial consists of hands and facets. When the sun moves in the sky, the projection of the hand moves on the surface like the hands of a clock, which can indicate the time.

moment

Both the standard watch and the clepsydra use the shadow of the sun to calculate the time, but it will lose its function when it rains or it gets dark, so a kind of water clock that can time day and night is produced, which is the clepsydra. Leakage refers to the leakage of the pot; Carving means carving an arrow. The arrow is a ruler marked with a time scale. Missing carving is to calculate the time by observing the data displayed on the carved arrow in the pot by using the principle of balanced dripping. As a timer, cracks are more common than sundials. In ancient China, many literati and poets left many poetic chapters about missing prints. For example, Li He, a poet in the Tang Dynasty, said, "It's like adding seawater to a palace leak and dropping Nagato overnight." Su Shi in Song Dynasty: "When the moon is absent, people are quiet." Before mechanical clocks and watches were introduced to China, nicking was the most widely used timer in China.

Question 4: What are the ancient timing instruments? The earliest timekeeping instrument used by human beings used the projection length and direction of the sun to judge time. The former is called a standard watch, which is used to measure the time between Japan and China, determine the season and identify the direction; The latter is called a sundial and is used to measure time. Both are collectively referred to as sun clock.

From BC 1300 to BC 1027, the use of standard meters was recorded in Oracle Bone Inscriptions during the Shang Dynasty in China. The Book of Songs? National wind? There is an article in Prescription, "Prescription was made in the palace of Chu. Slap the sky and attack the Chu room ... ". The exact record of using standard watches is 659 BC.

Sun clock, such as standard watches, will fail on cloudy days or at night. To this end, people have invented time-measuring instruments such as clepsydra, hourglass, oil lamp clock and candle clock.

In ancient China, there were mainly two kinds of timers designed by applying mechanical principles. One is timed by fluid mechanics, and there are notches and hourglasses later; One uses mechanical transmission structure to time, including armillary sphere and water transport instrument. In addition, there is a sundial that uses astronomical principles (mostly according to the direction of the sun's shadow to measure time), and it is also one of the oldest timepieces in China. Sundial, water clock, hourglass

Standard watches, sundials, water clocks, sand clocks, fire clocks, candle clocks, thousand-copper leaky rolling bombs, Yanyou dripping, dragon boat fragrant leaking, dragon water, equatorial sundial, equatorial theodolite, armillary sphere, etc.

sundial

The "table" in the standard table is a pole or stone pillar standing vertically on the ground; "Gui" is a slate extending horizontally from the heel of the watch to the north. Whenever the sun turns due south, the shadow falls on the water of Guiyu. By measuring the length of the shadow, we can calculate the time of each solar term, such as winter solstice and summer solstice. When the shadow is the longest, the solstice of winter comes; In the shortest time, the summer solstice came. It is the oldest and most common astronomical instrument in China. The sundial sundial is also an instrument for measuring time by observing the shadow of the sun, which mainly determines the time or the number of minutes at that time according to the position of the shadow. Judging from the unearthed cultural relics, the sundial was used before the Han Dynasty, and it was always a common timer before the mechanical clock was introduced to China. The main part of a sundial consists of hands and facets. When the sun moves in the sky, the projection of the hand moves on the surface like the hands of a clock, which can indicate the time. Both the leaky meter and the leaky meter use the shadow of the sun to calculate the time, but it will lose its function when it rains or it gets dark, so a kind of water clock that can time day and night is produced, which is the leaky meter. Leakage refers to the leakage of the pot; Carving means carving an arrow. The arrow is a ruler marked with a time scale. Missing carving is to calculate the time by observing the data displayed on the carved arrow in the pot by using the principle of balanced dripping. As a timer, cracks are more common than sundials. In ancient China, many literati and poets left many poetic chapters about missing prints. For example, Li He, a poet in the Tang Dynasty, said, "It's like adding seawater to a palace leak and dropping Nagato overnight." Su Shi in Song Dynasty: "When the moon is absent, people are quiet." Before mechanical clocks and watches were introduced to China, nicking was the most widely used timer in China. water clock

Also known as clepsydra and clepsydra. There are two main types of clepsydra: drainage type and water receiving type. Most of the early water leaks were drainage type. The bottom side of the leaky kettle leaks water, and the grid fork and the closing tongue rise again, so that the leaking arrow floating on the surface of the leaky kettle drops with the water surface, and the scale on the leaking arrow indicates the time. Later, the water-receiving type was created. Water is injected from the leaky kettle into the receiving kettle at a constant flow rate, and the leaking arrow floating on the water surface of the receiving kettle indicates the time with the rise of the water surface, thus improving the timing accuracy.

In order to obtain a constant flow, the water level of the clepsydra must be kept constant at first. Secondly, the cross-sectional area of the water pipe of the irrigation pot must be fixed, and the water pipe adopts the principle of "thirst for black" (siphon) to facilitate adjustment and maintenance. There are two ways to keep the water level unchanged or close to it, both of which can be found in "The Wind Map of Hu's Qi State" made by Yang Jia in Song Dynasty (published by 1 153). In the picture, there are several compensation pots carved above the leaky pot of Lv Caiding made in Tang Dynasty (about 600 ~ 650 AD), and Su Yanding made in modern times (1030) is carved by overflow method, which is four inches deep. Excess water flows from the flat kettle (lower cavity) into the water reduction angle through the bamboo injection tube. The leaky pot created by Yan Su is called Lotus Leak, which was popular all over the country in the Northern Song Dynasty.

The whole ancient three dynasties, Qin and Han dynasties, three kingdoms and six dynasties? Huan Tan (who died in 56 AD) said in an article that the leakage varies with the humidity, temperature and humidity, and it needs to be checked with reference to the sundial and the stars at night. At that time, the influence of water temperature and air humidity on the timing accuracy of engraving leakage was realized.

The earliest missing records can be found in Zhou Li. Most cultural relics were unearthed ... >>

Question 5: What are the ancient timing tools? 1. The sundial consists of a dial. The pointer is inserted in the center of the disk, and the dial is engraved with a scale indicating time. The needle shadow of the sun is projected on the cross line, which can indicate the time.

2. In rainy days and at night, it is engraved. Leaky carving, also known as leaky pot, includes a copper pot with a small hole under it and an arrow with scale engraved on it. Water flows at a constant speed, and the time can be determined by observing the change of water level through scale.

3. Monks and their entourage in the Tang Dynasty invented the earliest automatic alarm clock, which used water leakage to stimulate the wheels, turning once a day and night, mostly at 29 revolutions a month and 365 revolutions a year. At the same time, there are two Woodenhead, one drum at a time and one hour (equivalent to two hours).

4. In Yuan Dynasty, Guo Shoujing also invented mechanical clocks with different sounds.

5. People use more time-keeping methods such as burning incense and lighting candles.

Question 6: What are the commonly used running timers? Glug, Cheerios, Nike+, run wild!

Question 7: What timing tools were there in ancient times? In ancient China, people invented many timing methods or tools.

Guiyu is a simple and important astronomical instrument, which consists of a vertical watch (usually eight feet high) and a horizontal Guiyu. It uses direct facts to measure the length of the sun shadow. The main function is to determine the location of the winter solstice, and then determine the length of the tropical year. In addition, we can also determine the direction and solar terms by observing the changes of surface shadows.

The sundial (pronounced gu), also known as "sundial", is another kind of timing instrument in ancient China. It usually consists of a copper pointer and a stone disk. The pointer made of copper is called "needle" and the disk made of stone is called "face". When using, we can distinguish different times by observing the treatment of the shadow cast on the plate. The sundial can be timed accurately to the minute (15 minutes).

The dripping of copper pot is also called "leaky carving" or "leaky pot". That is, the water level of the copper pot is changed by the running water at the bottom of the pot or a water holding tool with a small hole near the bottom of the pot to calculate the time. The copper pot drip invented by China is much earlier than the drip timer made in foreign countries, and it is also widely used, which has become an important tool for timing in past dynasties.

In addition to the above-mentioned timing methods, people in ancient China also used "hourglass timing", "fire timing" and "candle timing" to time.

Question 8: What are the ancient timing tools? There are mainly the following categories:

There are two main types of timers designed by mechanical principle. One type uses fluid mechanics to time, and then there are notches and hourglasses. One uses mechanical transmission structure to time, including armillary sphere and water transport instrument. In addition, there is a sundial that uses astronomical principles (mostly according to the direction of the sun's shadow to measure time), and it is also one of the oldest timepieces in China.

Sundial introduction:

The sundial, the "table" in the sundial, is a pole or stone pillar standing vertically on the ground; "Gui" is a slate extending horizontally from the heel of the watch to the north. Whenever the sun turns due south, the shadow falls on the water of Guiyu. By measuring the length of the shadow, we can calculate the time of each solar term, such as winter solstice and summer solstice. When the shadow is the longest, the solstice of winter comes; In the shortest time, the summer solstice came. It is the oldest and most common astronomical instrument in China.

Question 9: At present, stopwatches, such as () and (), are commonly used timing instruments. It is timed by controlling the rotation of the pointer by using the isochronism of the pendulum. It has a large dial on the front and a small dial on it (Figure 1.4-2). The second hand rotates along the big dial and the minute hand rotates along the small dial. The total time indicated by the minute hand and the second hand is the time interval of measurement. There is a watch handle directly above the watch with a button on it. Turn the button and wind it up. This is the power of stopwatch movement. Press the button with your thumb and the stopwatch will start timing; Press the button again, the stopwatch stops moving and starts reading; Press it again, and the stopwatch will return to zero, ready for the next time. (Note: When using this stopwatch, you must complete this program before you can proceed to the next time. When this watch stops, you can't start the stopwatch. To solve this problem, some stopwatches have a button on the left side of the watch handle. When the watch moves, push this button up and the watch stops. Push down, that is, continue to accumulate opportunities. )

A metronome is an instrument that uses the synchronous binary beat sound of a pendulum to time.

Take off the metronome panel and you will see a scale. Represents the number of beats per minute when the pendulum vibrates (n). There is a pendulum in the middle, and a pendulum can move up and down on the pendulum. The number of scales opposite the pendulum position indicates the number of beats per minute of the pendulum (there are two beats in a complete vibration), from which the vibration period (t) of the pendulum can be calculated.

T = (2× 60)/t (second)

Changing the position of a pendulum can change its vibration period.

In order to tell the time conveniently, the lower part of the wooden box of metronome is equipped with a bell adjusting lever, which can make the bell ring every few beats. Remember the number of rings and find out the time interval (t)

T=T/2×R=R/n×60 (seconds)

R is the number of beats that ring once. By adjusting the position of the pull rod, the number of beats of a bell can be changed. If no vibration is needed, just push the pull rod completely.

Wind it first when using it, and be careful not to wind it too tightly. According to the experimental requirements, adjust the number of beats per minute and the ringing frequency. The metronome should be placed horizontally, and the amplitude of the pendulum should not be too large. Let the clockwork relax after use and pay attention to maintenance.

When in use, the timer should start from a certain ring.