The origins of online timer

Mechanical clocks were originally designed with swing or balance-time basis as timers.
The famous timers from that period is, perhaps, the alarm clock, or even the church bell, the bell at the set time prompted an internal mechanism or stroke.

Even in the first half of the 20 Century popular synchronous clocks had often switch contacts.Electromechanical switches for home use are often implemented as an adapter plug and have a switched outlet.

They online timer are driven by a synchronous motor, and is controlled as a Synchronous of the mains frequency. About coding slider can be set, at which time and off.Synchronous clocks have the disadvantage that they remain in power failure.Today online timer there are electronic, battery-quartz or radio controlled models with one relay output.

Almost all of these switches are either so-called seven-day clocks, which allow switching time programming on a certain day, or year time switches, which turn to a certain date.

Yearly timers have also always the functionality of a day time, thus also allowing a switching operation on a particular day of the week regardless of the current date.Timers in switchgear and controls are also fed from the mains. She formerly worked mechanically (train with balance, electric lift) and had a power reserve of a few days.Later was used a quartz movement with a stepper motor, one of the drive wheel train. These watches need a buffer battery to keep running during a power failure can.

Today electronic watches are used (quartz or radio-controlled), which usually have a relay as a switch.Some digital timers can not only preselected times on and off, but pseudo-random switching (eg evenings turn on the light, to the presence of fake) to determine summer and winter time, by synchronizing over the DCF77, or they determine shift points After years time dependent sunrises and sunsets (called Astro function).

Short-term timersShort timer (1 hour) with clockworkShort time switches do not operate according to the absolute time, but always switch one consumer for a preset period of time or delayed or out. Discrete components in controls are referred to as timers.

This includes exposure watches and automatic stairway lighting.Short timers operate mechanically, electro-mechanically connected to a synchronous motor, or electronically with a clock generator and a frequency divider.Previously, they were often operated with a pneumatic delay, a mechanical inhibition or an aerodynamic brake.In purely mechanical short-timers by pressing the delay start a spring mechanism is mounted. This design needs no operating current.Wall clocksA Signaluhr is a timer which at predetermined time points for a certain short duration makes electrical contact. For example, every day at 12 for three seconds clock is triggered a pause signal, such as the gong in a school or the signal for a shift change in a production operation.

A Signaluhr that generates momentum for slave clocks, called master clock. A Funksignaluhr use a radio clock for timing.Comparison of mechanical / digitalDigital time switchesDaily timer with 10steinigem balance-movement and motorized lift for network operation (power reserve 50 hours, built in 1987, VEB Glashütte watch factory DDRProvided with keys and a display, let digital timers accurate and - to any degree of complexity on / off times - depending on the equipment.

You need a battery to store the settings. As electronic timers have a relay, they consume additional power when the consumer (similar to Synchronous-timers).

Through the use of a bistable relay (impulse switch) can reduce the energy requirements are also in the ON state.Mechanical timersAnd the energy requirements of mechanical switches is small (less than 1 watt [1]). You do not need batteries and are easy to use. The switching intervals are at least 15 minutes. On / off intervals can be set intuitively. In case of power interruptions they stop and have to be reset.

They constantly consume power.Previously, there were also mechanical timers with a clockwork motor and an elevator or an electronic / mechanical quartz movement. This had the lowest energy consumption of all timers.Working with an inhibition and a spring plant short timers do not have their own electricity consumption.

A timer clock

A timer or clock is a clock that is at fixed times an electrical contact on or off. The switching times are typically adjustable.

For example, if the water daily 6 to 22 clock should be warm, at other times, however, to save energy, not to be heated, so a switch will be set so that the heating is switched on at 6:00 clock and by 22 : 00 clock goes off.

With normal switch the cycle repeats itself every 24 hours, at a weekly countdown timer can vary switching times are set individually for each weekday. The hot water heater could be set at a weekly time so that on Saturdays and Sundays from 8 to 23 clock should be heated.
With a yearly for each calendar, different switching times are set. Thus, even holidays or special events are included in the settings.

There are two types of switches, mechanical and electronic. In mechanical switches, a motor rotates a disk, are inserted into the pins or the like. These pins then press the contact directly. Electronic timers can be programmed using a display and buttons on the device.
To control short switching signals, such as a bell in a school, signal watches are used.Types and time baseAbsolute time-timers

Mechanical clocks were originally designed with swing or balance-time basis as timers. The famous timers from that period is, perhaps, the alarm clock, or even the church bell, the bell at the set time prompted an internal mechanism or stroke.

Even in the first half of the 20 Century popular synchronous clocks had often switch contacts.
Electromechanical switches for home use are often implemented as an adapter plug and have a switched outlet. They are driven by a synchronous motor, and is controlled as a Synchronous of the mains frequency. About coding slider can be set, at which time and off.

Today there are electronic, battery-quartz or radio controlled models with one relay output. Almost all of these switches are either so-called seven-day clocks, which allow switching time programming on a certain day, or year time switches, which turn to a certain date. Yearly timers have also always the functionality of a day time, thus also allowing a switching operation on a particular day of the week regardless of the current date.

Timers in switchgear and controls are also fed from the mains. She formerly worked mechanically (train with balance, electric lift) and had a power reserve of a few days.Later was used a quartz movement with a stepper motor, one of the drive wheel train. These watches need a buffer battery to keep running during a power failure can. Today electronic watches are used (quartz or radio-controlled), which usually have a relay as a switch.

Some digital timers can not only preselected times on and off, but pseudo-random switching (eg evenings turn on the light, to the presence of fake) to determine summer and winter time, by synchronizing over the DCF77, or they determine shift points After years time dependent sunrises and sunsets (called Astro function).

The online timer

A timer is a device or minutes, often programmable measuring time. The first generation were hourglasses, clocks that were replaced later by a conventional electronic device entirely. When time passes is configured to skip an alarm or another function as a warning.
household

A online timer can be a cooking utensil to control the cooking time. Often integrated in conventional ovens or microwave ovens. Also appliances such as washing machine or dryer is equipped with timers.

Currently most electronic devices such as mobile phones or personal computers, have a timer function.
Socket with a timer.

A timer can also be used as a simulator of presence, allowing an electronic device (such as a radio or light) stays on for a predetermined time, to prevent theft. Also can be used as a device connected to electricity is connected or disconnected at any given time (relative, eg. At one time or absolute, eg. At 13 hours). This is especially useful for those devices that do not have their own or a timer that can be programmed.
other Uses

Countdown - countdown device, signal - usually sound, such as a bell - before the passage of the set number of minutes. Used, among others in the household, such as in the kitchen, where he helps ensure proper cooking time.

Mechanical timers usually work on the principle of using a spring mechanism: turning the knob on the pitch angle adjustable graduated in minutes start slow rotation of the wheel, which is approximately as long as the set due to graduation. Newer solutions, electronic components and electronic displays, usually provide more precise timing, accurate to seconds. In today's mobile phones, it is common to install timers among the various helper applications, usually regardless of the timer.The timer is an important element in many fields, such as in biological laboratories, which can precisely control the exposure time, such as enzymatic digestion.

Also used for the detonation of explosive s, allowing evacuate an area of ​​danger.


The timer is a clock device, program or other mechanism by which a particular activity or event for starting and end times may be controlled. The timer is different from that display the time clock in the fact that its main purpose is not to show the time, but to convey the information reaching the time limit, or cause an event at a particular time or after a certain time.
A simple digital timer. Picture of a timer includes a control circuit, LED display, battery and buzzer.

Implementation in the timer may be mechanical, electromechanical, chemical, electronic or software.

A typical example is a mechanical online stopwatch timer cooking clock or egg timer. The fuse is a chemical timer. Dry the timer may be based, for example, an acid, which is corrosive to certain period of time Timer device locks the safety catch. A soft timer is a logical structure, which delays the progress of the program until a desired number of repetitions is completed or further condition is met.
The timer circuit

Traditional timer circuits 8253 (PC) and 8254 (the AT) clock inputs is connected to a standard 1.193180 MHz crystal frequency. The frequency is 1/4 of the original IBM PC's clock frequency. Timer 0 IRQ0 is connected to the line. It typically causes an interruption at 18.2 times per second. Timer 0 Gate is permanently connected to the charts. These circuits are useful for their own timers interrupt routines Timing. They can also be used for precise measurement.

The countdown timer

Are specialized timer clock that can be used to measure the duration of the process or incoming event. The timer can be a simple movement can be electromechanical, digital or software (implemented as part of a computer program).
Online timer

Mechanical kitchen timer (the "timer").Mechanical timers typically used classic clockwork spring and anchor, which regulates their speed.

Cheaper and less accurate are machines with an aerodynamic brake.

Electromechanical timerElectromechanical timers are of two types - with bimetal strip or with an electric motor.

Bimetallic stripThe bimetal strip is formed by joining two metal strips of different thermal expansion coefficient (typically steel and bronze), which is heated by passing an electric current. Bending the tape will contact separation, cooling and re-tape making contact again and the cycle repeats.

This type of timer is used eg for the blinkers in cars at the lights on the Christmas tree or the time limit congestion at the circuit breaker.Electric motorSimple electromechanical timer with an electric motor.AC electric motor spins the gear that moves the anchor as well as the classic movement. Are attached to the anchor electrical switch contacts and the current through the motor is precisely controlled.

Sometimes sprocket connected to a friction clutch that could be easily timer returned to the starting position.This type of timer is used for example in the washing machine, tumble dryer, dishwasher or in universal time switch.

The timer can take the form of a separate device (see illustration at right) plug adapter when the device is directly controlled socket for appliance or modular unit for cabinet mounting. Programming the timer stops is done and it is just gross. Typically after čtvrthodinách.
Digital timer provides more configurable switching intervals.

Digital timer achieves higher accuracy than mechanical or electromechanical, because it contains electronic clocks, quartz and special integrated circuit. Use of integrated circuits has caused such a drop in prices of digital technology, digital timers that are now cheaper than most mechanical timers.

Timers are manufactured as single-chip embedded systems like electronic watch.Many digital timers is currently implemented in single-chip computers with the software or the use of programmable logic circuits using Boolean algebra.In simpler (mainly amateur or handmade) circuits used integrated circuit NE555.

Digital timers use complicated devices that require higher precision or variability timers, for example, more expensive washing machine, dryer, dishwasher, or timers with more advanced options when setting switching intervals (repetition, switching only on selected days of the week, odd and even weeks, etc.) .


The digital timer is produced in the form of plug adapter (pictured) as well as a modular unit in the cabinet. They are equipped with real-time backup of the program. Subtle, but ubiquitous timers are stair machines that control lighting in common areas home.

Similarly, work time delay relays for fans to be off welfare facilities. These relays are installed in wiring boxes under the switch.The timer on the computerMost computers contain one to 16 hardware timers.

They are usually counters that the program is set to a value, which is then automatically reduced. When it reaches zero, the interrupt caused by the CPU is notified.

The timer is used to control the software events, such as time-out while waiting for an answer on another computer (English timeout), management scheduler in the operating system, etc.