ETYM Latin valva the leaf, fold, or valve of a door: cf. French valve.
1. A structure in a hollow organ (like the heart) with a flap to insure one-way flow of fluid through it.
2. Any mechanical device for controlling the flow of a fluid.
3. Device in a brass wind instrument for varying the length of the air column to alter the pitch of a tone.
1. Zaklopac, poklopac (na posudi, satu, oku itd.);
2. Prozorsko krilo (tur.)
Organ kod ptica za letenje.
Deo mehanizma česme za vodu.
Oduška, mehanička naprava, obično od metala, pomoću koje se vrši otvaranje i zatvaranje propusta za vazduh, tečnosti, gasove, pare i dr., zalistak.
See electron tube, vacuum tube.
(electronics) or electron tube; In electronics, a glass tube containing gas at low pressure, which is used to control the flow of electricity in a circuit.
Three or more metal electrodes are inset into the tube. By varying the voltage on one of them, called the grid electrode, the current through the valve can be controlled, and the valve can act as an amplifier. Valves have been replaced for most applications by transistors.
However, they are still used in high-power transmitters and amplifiers, and in some hi-fi systems.
Zastarela tehnologija koja je korišćena na prvim računarima. Ovaj uređaj prenosi podatke tako što kontroliše protok elektrona, kao što to rade poluprovodničke diode i tranzistori u modernim računarima.
Device that controls the flow of a fluid. Inside a valve, a plug moves to widen or close the opening through which the fluid passes. The valve was invented by US radio engineer Lee de Forest (1873–1961).
Common valves include the cone or needle valve, the globe valve, and butterfly valve, all named for the shape of the plug. Specialized valves include the one-way valve, which permits fluid flow in one direction only, and the safety valve, which cuts off flow under certain conditions.
In animals, a structure for controlling the direction of the blood flow. In humans and other vertebrates, the contractions of the beating heart cause the correct blood flow into the arteries because a series of valves prevent back flow. Diseased valves, detected as “heart murmurs”, have decreased efficiency. The tendency for low-pressure venous blood to collect at the base of limbs under the influence of gravity is counteracted by a series of small valves within the veins. It was the existence of these valves that prompted the 17th-century physician William Harvey to suggest that the blood circulated around the body.
Poklopac u srcu.