Any electronics in the house can fail. However, you shouldn’t immediately run to the service center - even a novice radio amateur can diagnose and repair the simplest devices. For example, a burnt capacitor is visible to the naked eye. But what if you don’t have a part of a suitable value at hand? Of course, connect 2 or more in a chain. Today we’ll talk about concepts such as parallel and series connection of capacitors, we’ll figure out how to do it, learn about connection methods, and the rules for doing it.
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There is no capacitor of the required value: what to do
Very often, novice home craftsmen, having discovered a breakdown of the device, try to independently discover the cause. Having seen a burnt part, they try to find a similar one, and if this fails, they take the device for repair. In fact, it is not necessary that the indicators coincide. You can use smaller capacitors by connecting them in a circuit. The main thing is to do it right. In this case, 3 goals are achieved at once - the breakdown is eliminated, experience is gained, and family budget funds are saved.
Let's try to figure out what connection methods exist and what tasks the series and parallel connection of capacitors are designed for.
Connecting capacitors into a battery: methods of execution
There are 3 connection methods, each of which has its own specific purpose:
- Parallel– is performed if it is necessary to increase the capacity while leaving the voltage at the same level.
- Sequential– the opposite effect. The voltage increases, the capacitance decreases.
- Mixed– both capacitance and voltage increase.
Now let's look at each of the methods in more detail.
Parallel connection: diagrams, rules
It's actually quite simple. With a parallel connection, the calculation of the total capacitance can be calculated by simply adding all the capacitors. The final formula will look like this: C total = C₁ + C₂ + C₃ + … + C n . In this case, the voltage on each of their elements will remain unchanged: V total = V₁ = V₂ = V₃ = … = V n .
The connection with this connection will look like this:
It turns out that such an installation involves connecting all the capacitor plates to the power points. This method is the most common. But a situation may arise where it is important to increase the voltage. Let's figure out how to do this.
Serial connection: less commonly used method
When using the method of connecting capacitors in series, the voltage in the circuit increases. It consists of the voltage of all elements and looks like this: V total = V₁ + V₂ + V₃ +…+ V n . In this case, the capacity changes in inverse proportion: 1/С total = 1/С₁ + 1/С₂ + 1/С₃ + … + 1/С n . Let's look at changes in capacitance and voltage when connected in series using an example.
Given: 3 capacitors with a voltage of 150 V and a capacity of 300 μF. Connecting them in series, we get:
- voltage: 150 + 150 + 150 = 450 V;
- capacity: 1/300 + 1/300 + 1/300 = 1/C = 299 uF.
Externally, such a connection of plates (plates) will look like this:
This connection is made if there is a risk of breakdown of the capacitor dielectric when voltage is applied to the circuit. But there is another way of installation.
Good to know! Series and parallel connections of resistors and capacitors are also used. This is done in order to reduce the voltage supplied to the capacitor and prevent its breakdown. However, it should be borne in mind that the voltage must be sufficient to operate the device itself.
Mixed connection of capacitors: diagram, reasons for the need for use
This connection (also called series-parallel) is used if it is necessary to increase both capacity and voltage. Here, calculating the general parameters is a little more complicated, but not so much that it is impossible for a novice radio amateur to figure it out. First, let's see what such a scheme looks like.
Let's create a calculation algorithm.
- the entire circuit needs to be divided into separate parts, the parameters of which are easy to calculate;
- calculate denominations;
- We calculate the general indicators, as with sequential switching.
Such an algorithm looks like this:
The advantage of mixed inclusion of capacitors in a circuit compared to series or parallel
Mixed connection of capacitors solves problems that parallel and series circuits cannot do. It can be used when connecting electric motors or other equipment; its installation is possible in separate sections. Its installation is much simpler due to the possibility of performing it in separate parts.
Interesting to know! Many radio amateurs consider this method simpler and more acceptable than the previous two. In fact, this is true if you fully understand the algorithm of actions and learn to use it correctly.
Mixed, parallel and series connection of capacitors: what to look for when doing it
When connecting capacitors, especially electrolytic ones, pay attention to strict polarity. Parallel connection implies a minus/minus connection, and serial connection means a plus/minus connection. All elements must be of the same type - film, ceramic, mica or metal paper.
Good to know! Failure of capacitors often occurs due to the fault of the manufacturer, which skimps on parts (usually these are Chinese-made devices). Therefore, correctly calculated and assembled elements in the circuit will work much longer. Of course, provided that there is no short circuit in the circuit, in which the operation of capacitors is impossible in principle.
Capacitance calculator for series connection of capacitors
What to do if the required capacity is unknown? Not everyone wants to independently calculate the required capacitor capacity manually, and some simply don’t have the time for this. For the convenience of carrying out such actions, the editors of the site invite our dear reader to use an online calculator for calculating capacitors in series connection or calculating capacitance. It is extremely simple to work with. The user only needs to enter the required data in the fields and then click the “Calculate” button. Programs that contain all the algorithms and formulas for connecting capacitors in series, as well as calculating the required capacity, will instantly produce the required result.
A series connection refers to cases where two or more elements are in the form of a chain, with each of them connected to the other at only one point. Why are capacitors placed this way? How to do this correctly? What do you need to know? What features does series connection of capacitors have in practice? What is the result formula?
What do you need to know for a correct connection?
Alas, not everything here is as easy to do as it might seem. Many beginners think that if the schematic drawing says that an element of 49 microfarads is needed, then it is enough to simply take it and install it (or replace it with an equivalent one). But it is difficult to select the necessary parameters even in a professional workshop. And what to do if you don’t have the necessary elements? Let's say there is such a situation: you need a 100 microfarad capacitor, but there are several 47 microfarad capacitors. It is not always possible to install it. Go to the radio market for one capacitor? Not necessary. It will be enough to connect a couple of elements. There are two main methods: series and parallel connection of capacitors. That's the first one we'll talk about. But if we talk about the series connection of the coil and capacitor, then there are no special problems.
Why do they do this?
When such manipulations are carried out with them, the electric charges on the plates of individual elements will be equal: KE = K 1 = K 2 = K 3. KE - final capacitance, K - transmitting value of the capacitor. Why is that? When charges are supplied from the power source to the external plates, a value can be transferred to the internal plates, which is the value of the element with the smallest parameters. That is, if you take a 3 µF capacitor, and after it connect it to 1 µF, then the end result will be 1 µF. Of course, on the first one you can observe a value of 3 µF. But the second element will not be able to pass so much, and it will cut off everything that is larger than the required value, leaving a large capacitance on the original capacitor. Let's look at what needs to be calculated when connecting capacitors in series. Formula:
- OE - total capacity;
- N - voltage;
- KE - final capacity.
What else do you need to know to properly connect capacitors?
To begin with, do not forget that in addition to capacity, they also have a rated voltage. Why? When a series connection is made, the voltage is distributed inversely proportional to their capacitances between themselves. Therefore, it makes sense to use this approach only in cases where any capacitor can provide the minimum required operating parameters. If elements that have the same capacitance are used, the voltage between them will be divided equally. Also a word of caution regarding electrolytic capacitors: When working with them, always carefully monitor their polarity. Because if this factor is ignored, series connection of capacitors can give a number of undesirable effects. And it’s good if everything is limited only to the breakdown of these elements. Remember that capacitors store current, and if something goes wrong, depending on the circuit, a precedent may occur that will result in other components of the circuit failing.
Current in series connection
Because it only has one possible flow path, it will have the same value for all capacitors. In this case, the amount of accumulated charge has the same value everywhere. It doesn't depend on the capacity. Look at any diagram of a series connection of capacitors. The right facing of the first is connected to the left of the second and so on. If more than 1 element is used, then some of them will be isolated from the general circuit. Thus, the effective area of the plates becomes smaller and equals the parameters of the smallest capacitor. What physical phenomenon underlies this process? The fact is that as soon as a capacitor is filled with an electric charge, it stops passing current. And then it cannot flow throughout the entire chain. In this case, the remaining capacitors will also not be able to charge.
Voltage drop and total capacitance
Each element dissipates tension a little. Considering that the capacity is inversely proportional to it, the smaller it is, the greater the drop will be. As mentioned earlier, capacitors connected in series have the same electrical charge. Therefore, by dividing all expressions by the total value, you can get an equation that shows the entire capacity. This is where series and parallel connection of capacitors are very different.
Example #1
Let's use the formulas presented in the article and calculate several practical problems. So we have three capacitors. Their capacitance is: C1 = 25 µF, C2 = 30 µF and C3 = 20 µF. They are connected in series. It is necessary to find their total capacity. We use the corresponding equation 1/C: 1/C1 + 1/C2 + 1/C3 = 1/25 + 1/30 + 1/20 = 37/300. We convert to microfarads, and the total capacitance of the capacitor when connected in series (and the group in this case is considered as one element) is approximately 8.11 μF.
Example No. 2
Let's solve one more problem to consolidate our work. There are 100 capacitors. The capacity of each element is 2 μF. It is necessary to determine their total capacity. You need to multiply their number by the characteristic: 100*2=200 µF. So, the total capacitance of the capacitor when connected in series is 200 microfarads. As you can see, nothing complicated.
Conclusion
So, we have worked through the theoretical aspects, analyzed the formulas and features of the correct connection of capacitors (in series), and even solved several problems. I would like to remind readers not to lose sight of the influence of rated voltage. It is also desirable that elements of the same type be selected (mica, ceramic, metal-paper, film). Then series connection of capacitors can give us the greatest beneficial effect.
Capacitors, like resistors, can be connected in series or in parallel. Let's consider the connection of capacitors: what each of the circuits is used for, and their final characteristics.
This scheme is the most common. In it, the capacitor plates are connected to each other, forming an equivalent capacitance equal to the sum of the connected capacitances.
When connecting electrolytic capacitors in parallel, it is necessary that the terminals of the same polarity be connected to each other.
The peculiarity of this connection is equal voltage across all connected capacitors. The rated voltage of a group of parallel-connected capacitors is equal to the operating voltage of the group capacitor for which it is minimal.
The currents flow through the capacitors of the group are different: a larger current will flow through a capacitor with a larger capacitance.
In practice, a parallel connection is used to obtain a capacitance of the required size when it falls outside the range produced by industry or does not fit into a standard series of capacitors. In power factor control systems (cos ϕ), the change in capacitance occurs due to the automatic connection or disconnection of capacitors in parallel.
In a series connection, the capacitor plates are connected to each other, forming a chain. The outer plates are connected to the source, and the same current flows through all capacitors of the group.
The equivalent capacitance of capacitors connected in series is limited to the smallest capacitance in the group. This is explained by the fact that as soon as it is fully charged, the current will stop. You can calculate the total capacitance of two series-connected capacitors using the formula
But the use of a serial connection to obtain non-standard capacitance ratings is not as common as a parallel one.
In a series connection, the power supply voltage is distributed among the capacitors of the group. This allows you to get a bank of capacitors designed for higher voltage than the rated voltage of its components. So, blocks that can withstand high voltages are made from cheap and small capacitors.
Another area of application for series connection of capacitors is related to the redistribution of voltages between them. If the capacitances are the same, the voltage is divided in half; if not, the voltage on a capacitor with a larger capacitance is greater. A device operating on this principle is called capacitive voltage divider.
Mixed connection of capacitors
Such circuits exist, but in special-purpose devices that require high accuracy in obtaining the capacitance value, as well as for their precise adjustment.
Almost any electronic board uses capacitors, and they are also installed in power circuits. In order for a component to perform its functions, it must have certain characteristics. Sometimes a situation arises when a necessary element is not on sale or its price is unreasonably high.
You can get out of this situation by using several elements, and the necessary characteristics are obtained by using parallel and series connections of capacitors to each other.
A little theory
A capacitor is a passive electronic component, with a variable or constant capacitance value, which is designed to accumulate charge and energy from an electric field.
When choosing these electronic components, we are guided by two main characteristics:
The symbol for a non-polar permanent capacitor in the diagram is shown in Fig. 1, a. For a polar electronic component, a positive terminal is additionally noted - Fig. 1, b.
Methods for connecting capacitors
Composing banks of capacitors allows you to change the total capacity or operating voltage. For this, the following connection methods can be used:
- sequential;
- parallel;
- mixed.
Serial connection
The series connection of capacitors is shown in Fig. 1, c. This connection is used mainly to increase the operating voltage. The fact is that the dielectrics of each element are located one behind the other, so with this connection the voltages add up.
Total capacity elements connected in series can be calculated using the formula, which for three components will have the form shown in Fig. 1, e.
After transformation into a more familiar form for us, the formula will take the form of Fig. 1, f.
If the components connected in series have the same capacities, then the calculation is greatly simplified. In this case, the total value can be determined by dividing the value of one element by their number. For example, if you need to determine what the capacitance is when two 100 μF capacitors are connected in series, then this value can be calculated by dividing 100 μF by two, that is, the total capacitance is 50 μF.
Simplify as much as possible calculations of series connected components, allows the use of online calculators, which can be found on the Internet without any problems.
Parallel connection
Parallel connection of capacitors is shown in Fig. 1, g. With this connection, the operating voltage does not change, and the capacitances are added. Therefore, to obtain high-capacity batteries, parallel connection of capacitors is used. You don’t need a calculator to calculate the total capacity, since the formula has the simplest form:
C sum = C 1 + C 2 + C 3.
When assembling a battery to start three-phase asynchronous electric motors, a parallel connection of electrolytic capacitors is often used. This is due to the large capacity of this type of element and the short startup time of the electric motor. This mode of operation of electrolytic components is acceptable, but you should choose those elements whose rated voltage is at least twice the mains voltage.
Mixed inclusion
Mixed connection of capacitors - a combination of parallel and serial connections.
Schematically, such a chain may look different. As an example, consider the diagram shown in Fig. 1, d. The battery consists of six elements, of which C1, C2, C3 are connected in parallel, and C4, C5, C6 are connected in series.
The operating voltage can be determined by adding the rated voltages C4, C5, C6 and the voltage of one of the parallel-connected capacitors. If parallel-connected elements have different rated voltages, then the smaller of the three is taken for calculation.
To determine the total capacity, the circuit is divided into sections with the same connection of elements, calculations are made for these sections, after which the total value is determined.
For our scheme, the sequence of calculations is as follows:
- We determine the capacity of parallel connected elements and denote it C 1-3.
- We calculate the capacity of series-connected elements C 4-6.
- At this stage, you can draw a simplified equivalent circuit, in which, instead of six elements, two are depicted - C 1-3 and C 4-6. These circuit elements are connected in series. It remains to calculate such a connection and we will get the desired one.
In life, detailed knowledge about mixed connections can only be useful to radio amateurs.
In electrical engineering, there are various options for connecting electrical elements. In particular, there is a series, parallel or mixed connection of capacitors, depending on the needs of the circuit. Let's look at them.
Parallel connection
A parallel connection is characterized by the fact that all the plates of electrical capacitors are connected to the switching points and form batteries. In this case, when charging the capacitors, each of them will have a different number of electrical charges with the same amount of energy supplied
Parallel mounting schemeThe capacitance for parallel installation is calculated based on the capacitances of all capacitors in the circuit. In this case, the amount of electrical energy supplied to all individual two-pole elements of the circuit can be calculated by summing the amount of energy placed in each capacitor. The entire circuit connected in this way is calculated as one two-terminal network.
Ctot = C 1 + C 2 + C 3
Diagram - voltage on drives Unlike a star connection, the same voltage is applied to the plates of all capacitors. For example, in the diagram above we see that:
V AB = V C1 = V C2 = V C3 = 20 Volts
Serial connection
Here, only the contacts of the first and last capacitor are connected to the switching points.
Diagram – serial connection diagram The main feature of the circuit is that electrical energy will flow in only one direction, which means that the current in each of the capacitors will be the same. In such a circuit, for each storage device, regardless of its capacity, equal accumulation of passing energy will be ensured. You need to understand that each of them is in sequential contact with the next and previous ones, which means that the capacity of the sequential type can be reproduced by the energy of the neighboring storage device.
The formula that reflects the dependence of the current on the connection of capacitors is as follows:
i = i c 1 = i c 2 = i c 3 = i c 4, that is, the currents passing through each capacitor are equal to each other.
Consequently, not only the current strength will be the same, but also the electric charge. According to the formula, this is defined as:
Q total = Q 1 = Q 2 = Q 3
And this is how the total total capacitance of capacitors in a series connection is determined:
1/C total = 1/C 1 + 1/C 2 + 1/C 3
Video: how to connect capacitors in parallel and series method
Mixed connection
But, it is worth considering that to connect different capacitors, it is necessary to take into account the network voltage. For each semiconductor, this indicator will differ depending on the capacitance of the element. It follows that individual groups of small-capacity semiconductor biterminals will become larger when charging, and vice versa, a large-sized electrical capacitance will require less charging.
Scheme: mixed connection of capacitors There is also a mixed connection of two or more capacitors. Here, electrical energy is distributed simultaneously using parallel and series connections of electrolytic cells in a circuit. This circuit has several sections with different connections of condensing two-terminal networks. In other words, on one the circuit is connected in parallel, on the other - in series. This electrical circuit has a number of advantages compared to traditional ones:
- Can be used for any purpose: connecting an electric motor, machine equipment, radio equipment;
- Simple calculation. For installation, the entire circuit is divided into separate sections of the circuit, which are calculated separately;
- The properties of the components do not change regardless of changes in the electromagnetic field or current strength. This is very important when working with opposite two-terminal networks. The capacitance is constant at a constant voltage, but the potential is proportional to the charge;
- If you need to assemble several non-polar semiconductor two-terminal networks from polar ones, then you need to take several single-pole two-terminal networks and connect them in a back-to-back (triangle) manner. Minus to minus, and plus to plus. Thus, by increasing the capacitance, the operating principle of a bipolar semiconductor changes.