Since then, as the von Kleist - not a military leader, a priest - has decided to grasp the hand jar (bottle) filled with water, with lowered to the electrode, it took a long time. capacitor designs a great many today. Powerless to promise to consider 100% will give the concept of the capacitor operating principles, technical characteristics. We hope the review will be successful.
Gently running capacitor: the history of the Leyden jar
Simply start a static charge. It is noted scientists can accumulate electricity conductor surface. The distribution density of the same area. Keyword metals unlike dielectrics accumulating charge. Obzhivaya piece of iron, carriers tend to occupy the extreme position, pushing each other out. As a result, accumulate uniformly across the surface.
On the principle established generators capable to accumulate charge unit capacity of millions of volts. When you touch the current-carrying part of a person simply incinerated. Similarly, capacitors act. Shaped conductors, the area of which is greatly exaggerated. Achieved by various methods. The electrolytic capacitors aluminum foil rolls roll. Small cylinder comprises a metal strip meters.
varieties of capacitors
Let us explain the operation. When a metal (the conductive surface) appears charge, surface distribution starts. In 1745 the priest-lawyer Ewald Jurgen von Kleist discovered by holding in the hands of a jar of water stores in electricity. Palm serves as a conductive electrode, the volume of fluid (at the outer surface) - another. Glass serves dielectric barrier. When lowering the electrode into the water carriers tend to occupy the extreme position, plowing surface. Through the glass field acts on the palm, responsively start similar processes (charge attracts carriers of opposite sign).
Later guessed capacity wrap foil turned Leyden jar - a first capacitor capable in the world, invented by man. It happened when Pieter van Musschenbroek impressed force produced during the experiment electric shock. It became clear: the experiments are not safe, the hand should be replaced. The scientists wrote a second time avoids any chances for the sake of the kingdom of France. Dane Daniel Gralat was the first to guess connect the Leyden jar in parallel to provide higher capacity system. Reminiscent of a modern lead battery idea.
Funny, such devices were used until 1900, part of the everyday life of forced radio to seek new ways to solve problems, the use of relatively high frequency electrical signals. The result was the first paper capacitors, oily web separated from each other by two plates folded foil cylinder. Gradually, with the development of production in other materials have been used as insulators:
The real breakthrough in the construction of capacitors occurred when people guessed dielectric layer to replace the oxidized surface of a metal oxide. This applies to electrolytic capacitors. One cylinder oxide coated foil. Most currently used etching (intentional oxidation action of aggressive media material), if the requirements Performance large anodizing applied. Allowing a smooth surface closely adjacent the electrode of opposite sign.
Plates are the oxidized foil and paper impregnated with an electrolyte. Separated by a thin layer of oxide, allowing a great capacity to tens microfarads relatively small volume. Technical characteristics of capacitors are stunning. The second roll of aluminum foil will serve as a simple conductor of electricity, it is considered one contact. Oxide characterized surprising property - conducts current in one direction. When connecting the wrong side of the electrolytic capacitor is an explosion (destruction of the dielectric, electrolyte boiling, steam formation, rupture of the shell).
Refusing to serve as a dielectric separation layer becomes a conductor. Due to the sharp rise in the temperature region begins avalanche reaction between the metal and the electrolyte, the capacitor swells. Seen many hams, avoid telling process will provide a fun little attentive viewer.
Why the capacitor dielectric
It has been observed that if placed between the plates of a capacitor insulating material, the capacity increases. Long puzzled scholars, the concept of the dielectric constant has been disclosed. It appears, according to Gauss theorem, can be related to the capacity of the capacitor plates of the field strength. So, the insulator provides charge accumulation metals collecting surface carriers of opposite sign. We believe readers will have guessed: they create a field directed toward the source, causing a weakening of that increase design capacity.
the capacitor dielectric
The tables show: paper, ceramics do not look the best materials. Values of sulfuric acid up to 150 units by almost two orders of magnitude higher. Moreover pure substance recognized insulator. Probably one day capacitor the principle of operation will be implemented no solution, and sulfuric acid. Known lead-acid batteries in another store energy (reaction). The above options are not the only wider spread.
Globally capacitors divide by two families:
- Electrolytic (polar).
Told the first arrangement. The difference is limited to the material plates. The titanium oxide is provided with a dielectric constant close hundred. Clearly, the preferred material for the creation of high quality products. Cost bites. barium titanate exhibits a dielectric constant higher. Virtually any capacitor formed by the electrodes. Dielectric adds capacity product. Most often the best models of capacitors contain precious metals: palladium, platinum.
Labeling, specifications capacitors
Marking capacitors comprises setting the maximum permitted operating voltage. Designation is according to GOST 25486, then clarify reach industry standards. For example, the nominal value in accordance with GOST 28364 affixed. Individual standards almost impossible to find on the electrolytic capacitors. However, the authors have done, the reader is invited to peruse GOST 27550. The main body of all types of capacitors contain markings:
- manufacturer's logo.
- capacitor type.
It is difficult to say definitely, most electrolytic capacitors are marked with letter-K, several figures, often separated by a hyphen. Logically, we find in the Internet the appropriate standard or other materials.
- Under the rules of GOST 28364, the nominal value consists of 3-5 characters, the letter is present.
N means the prefix pico, n - nano microns - Micro. If the value of the fractional part is supplemented, in last place, vosled letters. The capacitive series (incomplete) GOST 28364 values given in the examples. Fulfilled the norm of this standard practice? Not for electrolytic capacitors. Caused, apparently, big denominations. Easily to meet K50-6 inscription like 2000 uF. According to GOST 28364, it should look something like 2M0. For electrolytic capacitors used GOST 11076. Along with coded symbols (GOST 28364) allowed the traditional record (2000 uF). You see, the purpose of capacitors often determines the method of marking. Electrolytic often serve an integral part of the food chain filters. It needs a high-value, functionality is very different principle of operation of capacitors separating the branches of alternating current circuits.
- If for the old standards the operating voltage of the capacitor marked tied for first place in the modern models vice versa. The designation is expressed volts.
The designations of the electrolytic capacitor
It is meant operating voltage without breakdown. Capacitor installation easily burned, the burned high values. A dielectric layer thinner, easier breakdown occurs. There is a contradiction between the distance separating the electrode (less - above nominal) and the desire to increase the operating voltage.
- Capacitance tolerance often ignored.
The aging process brings the nominal value of the range. We can say that is why there is a capacitor, not to manufacture using expired products. However, the hams are doing in their own way. Prozvanivatsya capacitor define a new denomination, enlisting the help of a tester used.
- The letter stands for all weather climatic performance capacitors.
- Before charging the capacitor try to understand whether the (electrolytic) polar.
The product is able to explode. Of course, the polar capacitor can not be included in the AC circuit. A single type of labeling is not provided, the paper specifies: requirements can be specified industry specifications. For example, the plus / minus sign. On imported products negative pole is marked with a light stripe dark body.
- Designation completes the release date (month, year), price.
Clearly, the latter with the current economic conditions irrelevant.
Please note, the capacitor is able to store a charge for a long time. It is fraught with the danger of electric shock. Any technician working with radio equipment, knows that top repair switching power supply precedes the capacitor discharge process. Often done with the help of the banned bulbs standards, screwed into the socket. Two bare wires to close the current-carrying part of the chain, the momentum briefly lights spiral. By the way, the design is often inserted to replace the fuse, to understand, still there is great current in the circuit (means there is a malfunction, causing the need for further diagnosis).
Troubleshooting capacitor requires skill, if you have specific knowledge feasible. You need to have on hand a simple multimeter. We have been told how to test a capacitor using a tester, directs the reader to the appropriate review themselves with the permission of the venerable public hasten to leave.