Capacity of the condenser is defined as the external characteristic geometrical dimensions of the device and also the nature and the size of the core of the condenser if it is used.
It is required to you
- The textbook in physics, the computer with the connected Internet.
Instruction
1. Pay attention to determination of capacity of the condenser in the textbook in physics. It is known that the capacity of the condenser is the relation of the charge saved on one of its facings to tension between facings. Thus, it is possible to increase or reduce condenser capacity, changing quantity of a charge which it can keep in itself(himself) at this value of tension.
2. Penetrate into the principle of operation of the condenser to understand how it is possible to change quantity of charges on its facings. When giving tension on condenser facings in it electric field which holds charges on plates is created. Thus, for increase in quantity of a charge on plates of the condenser it is necessary to increase electric field in it. For these purposes usually use the substances called polarizers.
3. Polarizers represent dielectric substances, atoms or molecules of which have polarizing properties. Thus, in the thickness of a polarizer besides the external electric field created by charges of facings there is own electric field induced by external. Own electric field of dielectric of the condenser is formed due to identical orientation of polar particles of substance of dielectric. Thus, internal electric field is imposed on external electric field, increasing it and creating an opportunity to save bigger quantity of charges.
4. Consider that various polar substances are capable to create various internal electric field. Thus, passing from one dielectric to another placed in the condenser it is possible to change its capacity sharply.
5. Notice also that it is possible to change number of charges on facings, having just changed the geometrical sizes of the device, namely, having changed the area of facings of the condenser. If you pay attention to a formula for the capacity of the plane-parallel condenser, you will see that it represents the relation of the area of its facings to distance between them increased by a dielectric constant of this substance. Thus, it is possible, having reduced distance between facings, to increase electric field in the condenser, thereby increasing condenser capacity.
6. Pay attention that dependence of capacity of the condenser on distance between its platinum sharper, than dependence of capacity on the area of facings. Therefore more reasonable is the way of change of capacity by means of change of distance between facings.