محمد مدحت Admin
عدد الرسائل : 35 تاريخ التسجيل : 19/01/2007
| موضوع: wimshurst machine ماكنة ومز هرست الجمعة يوليو 31, 2009 6:25 pm | |
| Was designed in the nineteenth century , and acts like an electrophorus which automatically transfers charges continuously to two conductors . it consists essentially of two large coaxial glass plates , one behind the other , which have metal sectors A1 , A2 … , B1 , B2 … , shown diagrammatically in the figure below , spaced equally all round their circumference . fixed metal conductors , P , Q , have wire brushes at their ends , which rub against the metal sectors as they rotate past them . P and Q are roughly perpendicular to each other . Suppose the metal sector B1 is given a negative charge by touching it with a charged ebonite rod . a negative charge is then induced at the end A7 of P , and a positive charge at the end A1 . as the sector A1 rotates carrying a positive charge , it induces a negative charge on the metal sector then in the position B3 and a positive charge on the metal sector then in the position B9 . by following the induced charges on the metal sectors of the two glass plates , which are made to rotate in opposite directions , it can be seen that negative charges are carried towards the metal pointed " comb " X , and positive charges are carried towards the other " comb " Y . at X , the negative charges induce a positive charge on the points and a negative charge on the sphere at M . the positive charges stream from the points of X , and neutralize the charge on the metal sector , leaving the negative charge on M . similarly , by means of the comb Y , the sphere at N obtains an induced positive charge . the charges at M and N both increase until the insulation of the air breaks down , when a spark is obtained between them . مشاهدة الصور | |
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