Filter definition - What it is, Meaning and Concept

A filter is a device that retains certain elements and lets others through .The concept usually refers to the porous material that allows the transit of a liquid but blocks the particles that the fluid has in suspension.

For example: "I need to buy filters to prepare more coffee" , "In my house we have a water filter to drink directly from the tap" , "The mechanic recommended me to replace the oil filter of my car" .

In different contexts a filtration funnel is used which, equipped with a paper , allows the removal of impurities or solids from a solution: while these particles remain in the filter, the liquid passes to another container or container. filter paper or filter paper is used, to name a case, in the electric coffee makers .

An air filter , meanwhile, is used to remove pollen , dust and other solid particles that can be found in the environment.These filters are frequent in engine and building ventilation systems.

Cigarettes, meanwhile, present a filter to ensure that certain toxic particles present in the smoke are not inhaled by the smoker. filters tobacco are usually manufactured with cellulose.

There are also the electronic filters or electric filters , capable of discriminating certain frequencies of electrical signals that pass through them.There are filters analogs and digital filters .

Filter, finally, is the name of the system or selection process that consists in the elimination of candidates or applicants: “Of the thousand students who took the university entrance exam, eight hundred failed to pass the filter ”.