Cold cathode

I had find many products about cold cathode lamps from some websites such as


LED Cap Light
Super bright LED lamp with clip on cap,suible for camping, mountain climbing and outdoor..


Parisian Hand Painted Lamp Shade
The height of this lamp is 22 inches and the width of this lamp is 12 inches. This lamp will be a..And you can see more from royal table lamp rice light bulbs china auto lamps yard lights lamp ceramic oil lamp emergency fluoresent lamp street road lamp high power par38 line color light Cold Cathode Fluorescent LampA cold cathode is an element used within some Nixie tubes, gas discharge lamps, gas filled tubes, and vacuum tubes. The term 'cold cathode' refers to the fact that the cathode is not independently heated. In spite of this, the cathode itself may still operate at temperatures as high as if the cathode were heated.Cold cathode fluorescent lamps (CCFLs) are usually also called cold cathodes. Neon lamps are a very common example of a cold cathode lamp.Cold Cathodes remain popular for LCD backlighting and enthusiast computer case modders.Contents1 Electron emission 2 Details 3 See also 4 References 5 Patents 6 External links // Electron emissionA cathode is any electrode that emits electrons. When used in electrical and electronic devices (most fluorescent lamps, vacuum tubes, etc.), the cathode is explicitly heated, creating a hot cathode. By taking advantage of thermionic emission, electrons can overcome the work function of the cathode without an electric field to pull the electrons out. But if sufficient voltage is present, electrons can still be stripped even out of a cathode operating at ambient temperature. Because it is not deliberately heated, such a cathode is referred to as a cold cathode, although several mechanisms may eventually cause the cathode to become quite hot once it is operating. Most cold cathode devices are filled with a gas which can be ionized. A few cold cathode devices contain a vacuum.DetailsThe cathode is the negative electrode. Any gas discharge lamp has a pair of electrodes, acting as cathode and anode (the positive electrode). Both electrodes act alternating as anode and cathode because the devices run with alternating current.A standard ATX computer case fitted with blue and green Cold Cathode tubes.A cold cathode is distinguished from a hot cathode that is heated to induce thermionic emission of electrons. Discharge tubes with hot cathodes have an envelope filled with low pressure gas and containing a pair of cathodes. Examples are most common fluorescent lamps, high pressure discharge lamps and [completely-evacuated] electron tubes and vacuum fluorescent displays.The interior surface of cold cathodes are capable of producing secondary electrons at a ratio greater than unity (amplification) upon electron and ion impact. For accelerating of the ions to a sufficient velocity for creating free electrons from the cathode material, cold cathode discharge lamps need higher voltages than hot cathode ones, causing a strong electric field near the cathodes.Another mechanism for generating free electrons from a cold metallic surface is field electron emission. It is used in some x-ray tubes, the field electron microscope (FEM), and field emission displays (FEDs).Cold cathodes sometimes have rare earth coating on them for enhancing electron emission. Some types contain a source of beta radiation to start ionization of the gas that fills the tube. In such a tube, glow discharge around the cathode is usually minimized, in favor of a so called positive column, filling the tube. The best example is the humble neon lamp. Another good example is Nixie tubes. Nixie tubes too are cold cathode neon displays that also happen to be in-line, but not in-plane display devices.Conventional type CCFL inverterExample of the advanced type CCFL inverter for notebookA common cold cathode application is in neon signage and other locations where the ambient temperature is likely to drop well below freezing, The Clock Tower, Palace of Westminster (Big Ben) uses cold cathode lighting behind the clock faces where continual striking and failure to strike in cold weather would be less than ideal. Other examples include the thyratron, krytron, sprytron, and ignitron tubes. Large-scale cold cathode fluorescent lamps (CCFLs) have been produced in the past, and are still used today when shaped, long life linear light sources are required. Nowadays, miniature CCFLs are extensively used as backlights for computer liquid crystal displays, as well as LCD televisions. CCFL's lifespan vary in LCD televisions depending on transient voltage surges, humidity and temperature levels in usage environments. Additionally, CCFLs are used by computer modders to light the insides of their customized computer cases.Despite their name, cold cathodes don't necessarily remain cold as they operate; they can get painfully hot. In systems using alternating current but without separate anode structures, the cathodes alternate as anodes and the impinging electrons can cause substantial localized heating, often to red heat. The cathode may or may not take advantage of this heating to facilitate the thermionic emission of electrons when it is acting as a cathode. (Instant start fluorescent lamps definitely do...(and so on)


HID Xenon Headlight - H13-2
Place of Origin: China Model Number: BST-HIDH13-2 Certification: ISO9001, E-mark Terms..
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