Selenium, whose atomic number is 34 and atomic weight is 78.96, was discovered by Berzelius in 1817 and is placed in Group VIb of the periodic table — the sulphur sub-group. Selenium rarely occurs naturally, and then only in conjunction with native sulphur. The selenium content of the earth’s crust is computed as 1 × 10−5 - 8 × 10−5 %. The element has six stable isotopes with masses of 74, 76, 77, 78, 80 and 82, with an electron structure of the form 4s2 4p4 with electron arrangement in the orbits 6, 18, 2.
KeywordsTransient Voltage Native Sulphur Amorphous Selenium Battery Charger Current Overload
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