If you urgently need to repair the equipment, but the required capacitor is not there, then you can increase the capacitance of the capacitor, as is known from the school curriculum, by connecting several devices into one circuit.
Content
- Electric capacity
- Parallel connection
- Series connection of capacitors
- Mixed way
- Comparison of different options
Such a problem can also arise if, for example, the required denomination is not on sale, that is, for non-standard connections, for example, in radio engineering experiments.
Electric capacity
When connecting devices for condensing a charge, as a rule, technology is interested in the electrical capacity that will result.
Electric capacity shows the ability of a two-terminal network to accumulate charge in itself and is measured in farads. It may seem that the higher this value, the better, but in practice there is no way to create everything. possible capacities in the world, moreover, often this is not necessary, since in all devices used everyday, standard condensation devices are used.
It is possible to connect several condensing devices in a circuit, creating one condensing capacity, while the value of the characteristic value will depend on the type of connection, and for its calculation there are long-known formulas.
Parallel connection
There are two types of connecting devices in a circuit: serial and parallel. Each of them has its own properties, but, as a rule, parallel connection of capacitors is used.
Parallel connection has the following properties:
- The capacity of a composite two-port network increases in comparison with each individual device.
- The mains voltage does not change.
It is better to connect capacitors to increase capacitance, as the properties show, in this way. To do this, you need to connect the leads from each two-port network in groups: each of them has two leads. You need to create two groups: in one connect all the capacitors from one terminal, and in the second from the remaining.
With this connection, the devices for condensation form one container, therefore the following formula is correct: С = С1 + С2 +... СN, where N is the number of capacitors in the circuit.
For example, if there are nominal values of 50μF, 100μF and 150μF, then when connected in series, the total value in the circuit will be 300μF.
In real life, this connection is used quite often, for example, if it turned out in the calculations that such a two-pole device is required, which cannot be found on sale for sure. With this method, you can vary the capacitance of the capacitor as required, while not changing the voltage in the network.
Series connection of capacitors
Capacitor series properties:
- The capacity of series-connected devices for charge condensation, in contrast to the capacity of parallel-connected capacitors, decreases.
- The voltage across the appliances rises.
For such a connection, you just need to connect the terminals of the two-pole devices to one another, forming a chain: the output of the first will be connected to the output of the second, the remaining output of the second with the output of the third, and so Further.
Connection formula: 1 / (1 / C1 + 1 / C2 +… + 1 / CN), where N is the number of devices in the connection.
For example, there are three 100μF capacitors. 1/100 + 1/100 + 1/100 = 0.03μF. 1 / 0.03 = 33μF.
The charges will be distributed with an alternating sign, and the capacitive value will be limited only by the same for the weakest link in the chain. As soon as it receives its charge, the transmission of current in the circuit will stop.
Why then do you need a similar connection method? Such the chain is more stable and can withstand a higher voltage when connected to a circuit with a lower capacitive rating of the capacitor. However, there are devices on sale that already have the necessary properties, therefore, such a connection is practically not used in life, and if used, then for specific tasks.
Mixed way
Combines parallel and serial connections.
At the same time, for sections with a serial connection, the properties of a serial connection are characteristic, and for sections with a parallel connection, the properties of a parallel one.
It is used when neither the capacity nor the rated voltage of commercially available devices are suitable for the task. Usually this problem occurs in radio engineering.
To determine the total value of electrical capacity, you will first need to determine the same value for parallel-connected two-port networks, and then for their series connection.
Comparison of different options
| Capacity | Voltage | |
| Parallel | Is increasing | Does not change |
| Consistent | Decreases | Is increasing |
| Mixed | Changes | Is increasing |
To select a connection, you can use the following table. On the left is the type of connection of devices, on top are the properties of the device for charge condensation.
If you need to increase the capacity, then you need to use a parallel connection, and if you increase the voltage, then a serial connection. If both are required, then it will be necessary to calculate the mixed connection of capacitors in the circuit.
