Timers

Timers can be clocks, stopwatches or any mechanical or electronic device used for accurate timekeeping. Stopwatches count up from zero whilst timers count down. The display can be analogue or digital and for laboratory or fieldwork, they are usually shockproof and water-resistant. Stopwatches can be manually operated or fully-automated, in which the start and stop is controlled by sensors. Often double or triple display timers are used since they can measure more then one experiment or procedure simultaneously. Some devices include a timer, stopwatch and clock in one device. Controlled power strips can be plugged into a device and can be programmed to turn on and off at specific intervals over a day or even a week. Some devices contain an alarm system which can be audible or bright flashing LED. Digital timers with a crystal oscillator timing element contain a microchip which can be connected to external sensors or triggered by external events. Atomic wall clocks are accurate to one hundred billionth of a second. Timers are extremely important in all laboratories to measure the duration of an experiment or a procedure. Precision is vital because the findings or effects may vary after one millisecond and so quartz-powered devices are chosen.