High-voltage power devices

SiC should also be more effective than silicon or gallium arsenide particularly in microwave and millimeter-wave devices and in high-voltage power devices. 

The promising electronic properties of beta-silicon carbide are compared to those of other semiconductor materials in Table 8.3 of Ch. 8. A major advantage of this material is its high-temperature potential (>1000"C) which far surpasses that of other semiconductors. Beta-SiC should also be more effective than silicon or gallium arsenide particularly in microwave and millimeter-wave devices and in high-voltage power devices. The development of SiC as a semiconductor is still in the laboratory state. 

The concentration of 222Rn in air was determined with a radon measurement detector. The detector allows realizing continuous radon monitoring. It consists of an electronic unit and a scintillation cell. The electronic unit contains power supply, amplifier, discriminator, timer, counter, and indicator. The scintillation cell contains the zinc sulfide scintillator, photomultiplier, preamplifier, high voltage power supply and chamber with a volume of 200 mL over the scintillator. This chamber is filled with the gas to be analyzed. The air is either pumped or diffuses into the scintillation cell. The scintillation count is processed by electronics, and radon concentrations for predetermined intervals are stored in the memory of the device. 

Shenoy, P. M., and B. J. Baliga, The Planar 6H-SiC ACCUFET A New High-Voltage Power MOSFET Structure, IEEE Electron Device Letters, Vol. 18, Issue 12, December 1997, pp. 589-591. 

Capillary Zone Electrophoresis. The primary advantage of capillary electrophoresis can be found in the simplicity of the instrument. Basic experimental components include a high-voltage power supply, two buffer reservoirs, a fused silica capillary, and a detector. The basic setup is usually completed with enhanced features such as multiple injection devices, autosamplers, sample and capillary temperature controls, programmable power supplies, multiple detectors, fraction collection, and computer interfacing. 

Fig. 2.15. Schematic automated isocratic and gradient elution nemo-liquid chromatograph/ capillary electrochromatograph according Alexander et al. (reproduced from Ref. [44] with permission of the publisher). 1, high-voltage power supply (negative polarity) 2, platinum electrode 3, outlet reservoir vial 4, UV detector with on-column flow cell 5, nanocolumn 6, two-position switching valve 7, jack stand 8, fused-silica make-up adapter (split device) 9, ground cable 10, internal loop micro-injection valve 11, plexiglas compartment 12, autosampler 13, dynamic mixer 14, micro-LC pumps.

Suppose, in a ten dynode chain, each primary electron causes the emission of five secondary electrons. After the first dynode we would have five electrons, after the second 25, after the third 125, and so on. At the tenth dynode we would have 510 electrons. Thus the device is very sensitive. Photomultiplier tubes are available which respond well over the entire UV-visible region of the spectrum. The tubes are stable and long-lived, which is just as well, because they are expensive to replace. They require a well-stabilized high voltage power supply, which adds to the overall cost of the instrument. 

The main components of a CE system are a high-voltage power supply, a capillary, inlet and outlet buffer vials, a detector, and a data output and handling device such... 

Figure 4.85 Basic components of a CE system (1) fused-silica capillary (2) electrolyte vessels with electrodes (3) syringe-to-capillary adaptor (replaced in commercial instruments by pressure or vacuum-driven rinse) (4) sample vial raised to a level necessary for sample introduction by hydrostatic pressure (5) regulated high-voltage power supply (6) detector (7) data acquisition device.

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