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Timer
A timer or countdown timer is a type of clock that starts from a specified time duration and stops upon reaching 00:00. It can also usually be stopped manually before the whole duration has elapsed. An example of a simple timer is an hourglass. Commonly, a timer triggers an alarm when it ends. A timer can be implemented through hardware or software. ''Stopwatches'' operate in the opposite direction, upwards from 00:00, measuring elapsed time since a given time instant. '' Time switches'' are timers that control an electric switch. Hardware Mechanical Mechanical timers use clockwork to measure time. Manual timers are typically set by turning a dial to the time interval desired, turning the dial stores energy in a mainspring to run the mechanism. They function similarly to a mechanical alarm clock, the energy in the mainspring causes a balance wheel to rotate back and forth. Each swing of the wheel releases the gear train to move forward by a small fixed amount, causing t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Time Switch
A time switch (also called a timer switch, or simply timer) is a device that operates an electric switch controlled by a timer. Intermatic introduced its first time switch in 1945, which was used for "electric signs, store window lighting, apartment hall lights, stokers, and oil and gas burners." A consumer version was added in 1952. The switch may be connected to an electric circuit operating from mains power, including via a relay or contactor; or extra-low voltage, low voltage, including battery (electricity), battery-operated equipment in vehicles. It may be built into power circuits (as with a central heating or water heating, water heater timer), plugged into a AC power plugs and sockets, wall outlet with equipment plugged into the timer instead of directly into the power point; or built into equipment. Types Sleep timer A sleep timer is a function on many modern televisions and other electronic devices that shuts off the power after a preset amount of time. The sett ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cam Timer
A cam timer or drum sequencer is an electromechanical system for controlling a sequence of events automatically. It resembles a music box with movable pins, controlling electrical switches instead of musical notes. Description An electric motor drives a shaft arranged with a series of cams or a drum studded with pegs along its surface. Associated with each cam is one or more switches. The motor rotates at a fixed speed, and the camshaft is driven through a speed-reducing gearbox at a convenient slow speed. Indentations or protrusions on the cams operate the switches at different times. Complex sequences of opening and closing switches can be made by the arrangement of the cams and switches. The switches then operate different elements of the controlled system - for example, motors, valves, etc. A programmer may change or rearrange (reprogram) peg or cam positions. Much like the pegs in a music box cylinder activate the notes, in a drum sequencer, as the drum of the sequencer sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Washing Machine
A washing machine (laundry machine, clothes washer, washer, or simply wash) is a machine designed to laundry, launder clothing. The term is mostly applied to machines that use water. Other ways of doing laundry include dry cleaning (which uses alternative cleaning fluids and is performed by specialist businesses) and ultrasonic cleaning. Modern-day home appliances use electric power to automatically clean clothes. The user adds laundry detergent, which is sold in liquid, powder, or dehydrated sheet form, to the wash water. The machines are also found in commercial laundromats where customers pay-per-use. History Washing by hand Laundering by hand involves soaking, beating, scrubbing, and rinsing dirty textiles. Before indoor plumbing, it was necessary to carry all the water used for washing, boiling, and rinsing the laundry from a pump, Water well, well, or Spring (hydrology), spring. Water for the laundry would be hand-carried, heated on a fire for washing, and then poured i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stopwatch
A stopwatch is a timepiece designed to measure the amount of time that elapses between its activation and deactivation. A large digital version of a stopwatch designed for viewing at a distance, as in a sports stadium, is called a stop clock. In manual timing, the clock is started and stopped by a person pressing a button. In fully automatic time, both starting and stopping are triggered automatically, by sensor. The timing functions are traditionally controlled by two buttons on the case. Pressing the top button starts the timer running, and pressing the button a second time stops it, leaving the elapsed time displayed. A press of the second button then resets the stopwatch to zero. The second button is also used to record ''split times'' or ''lap times''. When the split time button is pressed while the watch is running it allows the elapsed time to that point to be read, but the watch mechanism continues running to record total elapsed time. Pressing the split button a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hourglass
An hourglass (or sandglass, sand timer, or sand clock) is a device used to measure the passage of time. It comprises two glass bulbs connected vertically by a narrow neck that allows a regulated flow of a substance (historically sand) from the upper bulb to the lower one due to gravity. Typically, the upper and lower bulbs are symmetric as they are usually manufactured by pinching a tube. The specific duration of time a given hourglass measures is determined by factors including the quantity and coarseness of the particulate matter and the neck width. Depictions of an hourglass as a symbol of the passage of time are found in art, especially on tombstones or other monuments, from antiquity to the present day. The form of a winged hourglass has been used as a literal depiction of the Latin phrase ("time flies"). History Antiquity The origin of the hourglass is unclear. Its predecessor the ''clepsydra'', or water clock, is known to have existed in Babylon and Egypt as early ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clock
A clock or chronometer is a device that measures and displays time. The clock is one of the oldest Invention, human inventions, meeting the need to measure intervals of time shorter than the natural units such as the day, the lunar month, and the year. Devices operating on several physical processes have been used over the Millennium, millennia. Some predecessors to the modern clock may be considered "clocks" that are based on movement in nature: A sundial shows the time by displaying the position of a shadow on a flat surface. There is a range of duration timers, a well-known example being the hourglass. Water clocks, along with sundials, are possibly the oldest time-measuring instruments. A major advance occurred with the invention of the verge escapement, which made possible the first mechanical clocks around 1300 in Europe, which kept time with oscillating timekeepers like balance wheels., pp. 103–104., p. 31. Traditionally, in horology (the study of timekeeping), the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relay
A relay Electromechanical relay schematic showing a control coil, four pairs of normally open and one pair of normally closed contacts An automotive-style miniature relay with the dust cover taken off A relay is an electrically operated switch. It has a set of input terminals for one or more control signals, and a set of operating contact terminals. The switch may have any number of contacts in multiple contact forms, such as make contacts, break contacts, or combinations thereof. Relays are used to control a circuit by an independent low-power signal and to control several circuits by one signal. They were first used in long-distance telegraph circuits as signal repeaters that transmit a refreshed copy of the incoming signal onto another circuit. Relays were used extensively in telephone exchanges and early computers to perform logical operations. The traditional electromechanical relay uses an electromagnet to close or open the contacts, but relays using other operati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dishwasher
A dishwasher is a machine that is used to clean dishware, cookware, and cutlery automatically. Unlike dishwashing, manual dishwashing, which relies on physical scrubbing to remove soiling, the mechanical dishwasher cleans by spraying hot water, typically between , at the dishes, with lower temperatures of water used for delicate items. A mix of water and dishwasher detergent is pumped to one or more rotating sprayers, cleaning the dishes with the cleaning mixture. The mixture is recirculated to save water and energy. Often there is a pre-rinse, which may or may not include detergent, and the water is then drained. This is followed by the main wash with fresh water and detergent. Once the wash is finished, the water is drained; more hot water enters the tub by means of an electromechanical solenoid valve, and the rinse cycle(s) begin. After the rinse process finishes, the water is drained again and the dishes are dried using one of several drying methods. Typically a rinse aid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turn Signal
Automotive lighting is functional exterior lighting in vehicles. A motor vehicle has lighting and signaling devices mounted to or integrated into its front, rear, sides, and, in some cases, top. Various devices have the dual function of illuminating the road ahead for the driver, and making the vehicle visible to others, with indications to them of turning, slowing or stopping, etc., with lights also indicating the size of some large vehicles. Many emergency vehicles have Emergency vehicle lighting, distinctive lighting equipment to warn drivers of their presence. History Early road vehicles used Oil lamp, fuelled lamps before the availability of electric lighting. The first Ford Model T used carbide lamps for headlights and oil lamps for tail lights. It did not have all-electric lighting as a standard feature until several years after its introduction. Dynamos for automobile headlights were first fitted around 1908 and became commonplace in 1920s automobiles. Trafficators—s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clockwork
Clockwork refers to the inner workings of either mechanical devices called clocks and watches (where it is also called the movement (clockwork), movement) or other mechanisms that work similarly, using a series of gears driven by a spring or weight. A clockwork mechanism is often powered by a clockwork motor, description of the clockwork motor in an antique phonograph consisting of a mainspring, a spiral torsion spring of metal ribbon. Energy is stored in the mainspring manually by ''winding it up'', turning a key attached to a ratchet (device), ratchet which twists the mainspring tighter. Then the force of the mainspring turns the clockwork gears, until the stored energy is used up. The adjectives ''wind-up'' and ''spring-powered'' refer to mainspring-powered clockwork devices, which include clocks and watches, kitchen timers, music boxes, and wind-up toys. History The earliest known example of a clockwork set-up is the Antikythera mechanism. This device functioned as a gear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synchronous Motor
A synchronous electric motor is an AC electric motor in which, at steady state, the rotation of the shaft is synchronized with the frequency of the supply current; the rotation period is exactly equal to an integer number of AC cycles. Synchronous motors use electromagnets as the stator of the motor which create a magnetic field that rotates in time with the oscillations of the current. The rotor with permanent magnets or electromagnets turns in step with the stator field at the same rate and as a result, provides the second synchronized rotating magnet field. Doubly fed synchronous motors use independently-excited multiphase AC electromagnets for both rotor and stator. Synchronous and induction motors are the most widely used AC motors. Synchronous motors rotate at a rate locked to the line frequency since they do not rely on induction to produce the rotor's magnetic field. Induction motors require '' slip'': the rotor must rotate at a frequency slightly slower than th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mainspring
A mainspring is a spiral torsion spring of metal ribbon—commonly spring steel—used as a power source in mechanical watches, some clocks, and other clockwork mechanisms. ''Winding'' the timepiece, by turning a knob or key, stores energy in the mainspring by twisting the spiral tighter. The force of the mainspring then turns the clock's wheels as it unwinds, until the next winding is needed. The adjectives wind-up and spring-powered refer to mechanisms powered by mainsprings, which also include kitchen timers, metronomes, music boxes, wind-up toys and clockwork radios. Modern mainsprings A modern watch mainspring is a long strip of hardened and blued steel, or specialised steel alloy, 20–30 cm long and 0.05-0.2 mm thick. The mainspring in the common 1-day movement is calculated to enable the watch to run for 36 to 40 hours, i.e. 24 hours between daily windings with a power-reserve of 12 to 16 hours, in case the owner is late winding the watch. This is the no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
