Basically a capacitor is a device capable of storing energy as electric field. It consists of two parallel metal armatures (usually aluminum) separated by a dielectric material.It has a number of features such as capacity, operating voltage, tolerance and polarity, that we learn to distinguish.In the simplest version the condenser is not put anything between the armor and the leaves with some separation, in which case it is said that the dielectric is air.
Measured in Farad (F), but this unit is so large that They are often used several submultiples, such as microfarads (10 -6 F = uF),nanofarad (nF = 10 -9 F) and picofarads (pF = 10 -12 F).
• Operating voltage:
The maximum voltage that can withstand a capacitor,depending on the type and thickness of the dielectric that is manufactured. If exceeded said voltage, the capacitor can be drilled (be short-circuited) and / or exploit. In this sense we must be careful when choosing a capacitor, so never work at a voltage higher than the maximum.
Same as resistors, it refers to the maximum error that can exist between the actual capacity of the capacitor and the capacity indicated on your body.
Electrolytic capacitors and generally higher capacity 1 uF have polarity, that is, that they must apply the voltage to provide attention to their positive and negative terminals. Unlike less than 1μF, to the voltage that can be applied in any direction, which have polarity They may explode if this be incorrect.
Types of Capacitors
We will show below a series of capacitors that are the most typical They can be found. They are compared in size to a Spanish coin 25 Ptas. (0.15 €).
Have the dielectric formed by electrolyte impregnated paper.Always they have polarity, and greater than 1 uF capacity. top note No clearly that the condenser 1 is 2200 uF, with a maximum voltage of 25v work. (Registration: 2200 μ / 25 V).Bottom left is a scheme of this kind of capacitors and the right are some examples of electrolytic capacitors certain size,those typically used in electrical applications (power supplies,etc…)
2- Electrolytic Tantalum or drop.
Used as a thin film dielectricAmorphous tantalum oxide, with a smaller thickness has an insulating power much higher. They have polarity and a capacity greater than 1 uF. Its teardrop It gives them many times that name.
3. MKT metallized polyester.
They usually have lower capacities than 1 uF and operating voltages from 63v. Below we see its structure: two sheets of polycarbonate coated with a metal deposit which are wound together. here the
side we see a detail of a flat capacitor of this type, which shows that It is 0.033 uF and 250v. (Enrollment: 0,033 K / 250 MKT).
They are similar to the above, although a manufacturing process something different. Sometimes such capacitors are in the form TV and bring their printed data in the form of color bands, receiving capacitors commonly called “flag”. Its capacity is usually 470 nF at most.
5- Tubular polyester.
Similar to the above, but normally coiled,uncrushed.
6- Ceramic “Lentil” or “disk”.
They are the most common ceramic. Their capacity values are pF between 0.5 and 47 nF. Sometimes They carry their data printed in the form of color bands.Below we see some examples of this type capacitors.
7. Ceramic “tube”.
Their capacity values are of the order of picofarads and generally no longer used, because of the large thermal drift with (variation capacity with temperature variations)
Color coding bands