The condensers are devices capable of storing a certain electricity quantity. They consist of two conductive surfaces, called armors put opposite to front and isolated between themselves by an insulating material that is called daléctrico. The aptitude to store electricity is proportional straight to the conflicting surface; inversely proportional at the distance that separates the armors and depends on the existing dielectric between both. If the dielectric is an air, it is said that the constant dieléctrica is 1. If between the armors there intervenes a badge of impregnated role, which constant dieléctrica is 3,50, there will obtain a condenser of 3,50 times more of capacity that the same one with air dielectric.
His aptitude to store electricity is provided by the following property: let's suppose, for example, a battery. In her we know that between his terminals a potential difference exists (d.d.p). which means that, ultimately, the principal function of this battery consists of moving the negative electrons that it possesses of more in his negative terminal and of gathering them in equal number in his positive terminal. If, for example, each of these poles gets connected to a driver, the electrons will be expelled by the driver top and they absorbed in the same number by the low one leaving the loaded top badge negatively and the low one positively. Thus it might be said that during a very brief second fraction there is established a very small current that it covers to fill the interior of every cable and that it stops because the circuit is not established. And so, we can say that the drivers store certain electricity quantity; and if one manages to disconnect these drivers of the terminals of the battery, of an instantaneous way, the load would remain in the drivers once separated from the source.
If in a this way conceived circuit we increase the thickness or the size of a driver, the capacity will increase proportionally; and if in a certain point of a circuit we apply a big surface, we will have managed to store here many major quantity of electrons of those who fit in a thin driver. Somehow we can compare a condenser with an abombamiento that existed in a circuit for which water happens. When the step of the liquid is interrupted, in the area of the abombamiento there remains imprisoned many more quantity of liquid than in the rest of the pipe.
The condenser is, then, a component deliberately made to have big capacity of storage of current; and this capacity depends, as we were saying at first, of the surface of the ties.
Functioning of a Condenser
Here we have an example of the functioning of a condenser opposite to an alternating current. We see a generator of alternating current that is connected to a condenser. Due to the alternate tension U, the condenser turns out to be loaded, unloaded, loaded again with opposite polarity; once again unloaded, and this way successively. With it it circulates a current which change is senoidal. But, the current does not circulate across the condenser, that is to say across his dielectric that is insulating as we have said, the current only circulates from the terminals of the generator to the armors of the condenser and vice versa, that is to say, although the circuit really is not closed the effect it is as if it it was; and being this one the effect, it usually say that along the circuit an electric current circulates.
The intensity of the current or, rather, the effective value of the alternating current depends, apart from the tension of the generator, of the capacity of the condenser and of the frequency of the proper alternating current. Major all that is the capacity and higher the frequency, with so many more violence develops the continuous load process and discharges and, consequently, so much more intense will be the current. To small capacities and frequencies only one current dweeb will circulate.
As for the direct current the behavior of the condenser is different. Here I gave there is a practical interpretation of the current. Opposite to the direct current the condenser behaves like a deposit that only is opened when the pressure of feeding (tension) changes. When the continuous tension increases, the current happens of + towards the pole-; when it becomes stable there is no current step, and when it diminishes the tension, the current circulates in inverse sense. The case of the alternating current turns out to be different because, as it is deduced of the explained earlier, this current with his phase changes loads and discharges successively to the condenser.
Inside an electronic circuit the condensers are used in the oscillating circuits joining his function to which they exercise the inductancias (or windings) making use of his conditions of step of the alternating current and blockade of the continuous one.
