How LED Operates 12 In order to have the light reflected as much as possible towards the surface of the device, a gold film is applied to the surface bottom, enabling to provide a cathode connection. All the wires in the electronic circuits of the device is protected by encasing the device. The light emitted by the device is dictated by the type of semiconductor material used – Infrared light is produced by using Gallium Arsenide (GaAs) as semiconductor, Red or yellow light is produced by using Gallium-Arsenide-Phosphorus (GaAsP) as semiconductor and Red or green light is produced by using Gallium-Phosphorus (GaP) as semiconductor. How LCD Operates In order to make an LCD screen, a reflective mirror has to be setup behind, with an electrode plane kept on top and a glass with a polarizing film placed on the bottom side. The entire area of the LCD has to be covered by a common electrode and above it should be the liquid crystal substance. Then, a piece of glass with an electrode in the shape of the rectangle on the bottom and, on top, another polarizing film; both kept at right angles. Without the presence of current, the light passing through the front of the LCD is reflected by the mirror and bounced back. Since the electrode is connected to a “temporary battery”, the current from it causes the liquid crystals in between the common-plane electrode and the rectangle-shaped electrode untwist and block the light from passing through, making that rectangular area appear blank.In short, when an electric current is applied to crystal molecules they untwist, causing a change in the light angle passing through them & in the angle of the top polarizing filter with respect to it. Little light is then allowed to pass through that particular area of LCD, that area becoming darker compared to others.For colour LCDs to work, 3 sub-pixels with red, green and blue colour filters must be present to create each colour pixel & to combining these sub-pixels, the LCDs should be connected to a large number of transistors.How CRT Operates Cathode ray tubes consist of one or more electron guns, (possibly internal electrostatic deflection plates) and a phosphor target. There are three electron beams – Red, Green, and Blue. The electron beam creates a small, bright spot upon striking the phosphor-coated screen. In every monitor device, the entire front area of the tube undergoes repeated, systematic scans in a fixed pattern (a raster). A raster is shown by scanning the electron beam across the screen. The phosphor’s targets start to fade after a short time, and the image will then need to be refreshed continuously, hence why CRT produces the three-colour images, which are the primary colours. How PCP Operates Two plates of glass are taken, with millions of tiny cells containing xenon and neon are filled in between. Electrodes are also placed inside the glass plates in a way that they are in front and behind each cell; The rear glass plate with the address electrodes sitting behind the cells, and the front glass plate with transparent display electrodes, surrounded by a magnesium oxide layer and a dielectric material, in front of the cell.As previously mentioned, when a voltage is applied, the electrodes get charged and lead to the ionization of the gas which result in plasma – this also includes the collision between the ions and electrons, causing the emission of photon light. The state of ionization differs according to colour plasma and monochrome plasma; for the latter, a low voltage is applied between the electrodes. To obtain colour plasma, the back of each cell has to be coated with phosphor. How CSMS Operates11 Physiologic monitors can be configured, modular, or both. Configured monitors have all their capabilities already built-in, and modular have separate modules for each parameter.Receivers are connected to a bedside monitor and/or a central station monitor, some of which have the capability of being networked, so a patient’s waveform can be simultaneously displayed at multiple locations within the hospital. Some telemetry systems allow receivers to be connected to a bedside monitor or to be used on the same central station network as hardwired bedside monitors. This allows the clinician to view a patient’s ECG and other monitored information at the bedside & at the central station.