A capacitor is a very common radio component that is found in all circuit diagrams. It consists of two conductors separated by a dielectric (depending on the type of capacitors, different types are used), that is, physically it is a circuit break, but a charge can accumulate in the dielectric. The main characteristic of any capacitor is the ability to accumulate charge - capacity, and the nominal voltage of this charge.
Electrolytic capacitors have a polarity and are characterized by a large capacity and a wide voltage range, paper capacitors withstand high voltage, but have a small capacity. There are also devices with variable capacity, but each type has its own application.
Often, radio amateurs are faced with the problem of selecting capacitors by capacitance or voltage. Professionals know: in the absence of what you need, you can assemble a combination of several devices, a battery of them. in batteriescombined, parallel and series connection of capacitors is allowed.
By connecting devices in parallel, you can increase the capacity. The total in such a battery will be equal to the sum of all capacities (Sekv.=C1 + C2 + …), the voltage on each element will be equal. This means that the minimum voltage of the capacitor used in the connection is the maximum allowed for the entire battery.
Series connection of capacitors is used when it is necessary to increase the voltage that can withstand devices or reduce their capacitance.
In this version, the elements are connected according to the following scheme: the beginning of one with the end of the other, that is, the "plus" of one with the "minus" of the other. The capacitance of the equivalent capacitor in this case is calculated according to the following formula: 1 / Seq. \u003d 1 / C1 + 1 / C2 + … less than the minimum capacity used in it.
A capacitor bank often provides a combined (mixed)connection. To calculate the capacitance of such a device, in which parallel and series connection of capacitors is used, the circuit is divided into sections, then the capacitance of each of them is calculated in turn. So, the capacity is calculated С12=С1+С2, and then Сeq=С12С3/(С12+С3).
Due to the creation of capacitor banks with various configurations and connections, you can choose anycapacitance for any voltage of interest. The series connection of capacitors, as well as the combined one, is used in many ready-made amateur radio circuits. At the same time, it is necessary to take into account the fact that each capacitor has a very important individual parameter - leakage current, it can unbalance the voltage in parallel connection and the capacitance in series. It is very important to select the required shunt resistance.
When working with capacitors and electronics, be aware of personal safety and the risk of electric shock.
