The timer clock

The online timer or timed relay is a relay with contacts special early or late that are constructed in such a way that the contact closes or opens earlier or later than in one instant. These contacts in the types of timing relays are also adjustable depending on the needs, generally from 10 to 800 seconds. Can be either delayed or the excitation-delayed. The timer in the electromechanical version also has a button or a small knob with three positions: off, on time and always on.

The timers can be used to:

     Into operation or closing or appliances.
     Synchronization.

Are in most often used as a timer to turn stairs.
Command / category

The timer can belong to several disciplines / areas:

     Electronic device created by electronic components, for example a Clock
     Electric device created by a coil that can be excited to delayed or retarded diseccitamento
     Computer program that determines the frequency of the various phases, is an example of the clock
Timer (from the English. Timer) - in computer science means of ensuring and measuring the time delay of the computer.
Interval is a function that allows some cameras to make images to a specified time interval. The intervallomètres used to watch slow phenomena as accelerated plant growth, moving clouds ...

Most modern digital cameras, including entry level, or could have had this opportunity. It depends only on the goodwill of manufacturers. On older cameras, you can sometimes add a programmable remote to the housing.

CHDK allows the project to introduce a script in addition to the embedded software in devices not equipped to lapse by the manufacturer. The "PowerShot" and "Digital Ixus" are the targets of CHDK project, it allows to increase the capabilities of these appareils1.The main characteristic is its timer accuracy - guaranteed to withstand a minimum amount of time. According to this parameter timers divided into:

     malotochnye (measurement error can be up to 0.1 s)
     accurate (measurement error is less than 0.001)
     -accuracy (measurement error is less than 10-6 c)

There are two types of timers:

     Hardware timers operate independently of the CPU at the time of operation and generate an interrupt.
     Program timers are implemented by executing a loop a specified number of identical "empty" operations. At a fixed frequency of the processor allows it to accurately determine the time elapsed. The main disadvantages of this method are: the dependence of the number of iterations of the type and frequency of the processor, the inability to perform other operations during the delay.