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The timer may switch equipment on, off, or both, at a preset time or times, after a preset interval, or cyclically. A countdown time switch switches power, usually off, after a preset time. A cyclical timer switches equipment both on and off at preset times over a period, then repeats the cycle; the period is usually 24 hours or 7 days.
A typical kitchen timer. A timer or countdown timer is a type of clock that starts from a specified time duration and stops upon reaching 00:00. 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.
A 7 cam 7 contact 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.
Coded panels were the earliest type of central fire alarm control, and were made during the 1800s to the 1970s. A coded panel is similar in many ways to a modern conventional panel (described below), except each zone was connected to its own code wheel, which, depending on the way the panel was set up, would either do sets of four rounds of code until the initiating pull station was reset ...
The first automatic timer, the dashpot timer has been used in many different machines and has many variations. Pneumatic, hydraulic-action, and mercury displacement timers. Being used in a variety of things such as printing presses , motors , and even irrigation systems , the dashpot timer has seen many applications.
The Intel 8253 PIT was the original timing device used on IBM PC compatibles.It used a 1.193182 MHz clock signal (one third of the color burst frequency used by NTSC, one twelfth of the system clock crystal oscillator, [1] therefore one quarter of the 4.77 MHz CPU clock) and contains three timers.
DIN rail mounted electronic lighting timer. An electronic timer allow simple push-buttons to be used. One timer is installed controlling the lights and any number of push-buttons, without pneumatic timers and connected in parallel, are used to trigger it. [1] [4] With many push-buttons, the cost savings for equipment may be substantial.
In data communications, an automatic switching system is a switching system in which all the operations required to execute the three phases of Information transfer transactions are automatically executed in response to signals from a user end-instrument.