A countdown timer is a device which is designed to count down to an end of particular talk. They range in design from simple mechanical devices like those used in electronic versions designed to be downloaded and installed on a laptop or as an individual stand alone. Numerous websites also use a countdown timer to mark the days, hours, minutes, and seconds until a major event, and some websites also generate countdown timer codes for installation on personal websites.
A basic mechanical countdown timer is usually very easy to use. The user manually sets the countdown timer to indicate the amount of time that needs to be counted down and turns it on. These types of timers are very useful for seminars, where there are a few presenters require timing so that they can keep track of how long they talk. Simple electronic countdown timers are designed to be used again and again in the same way: the user opens the program that runs the countdown timer, enters the necessary information, and starts it running. In both cases, when the countdown timer reaches the designated time, it usually makes some sort of signal such as a sound or light to indicate that the countdown is over.