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Everything here revolves around a central component in the world of electronics: the capacitor. Whether you are just starting out in electrical engineering or are already working on advanced projects, here you will find a comprehensive overview of the function, structure and various applications of capacitors. We also give you helpful tips on where to buy the best capacitors.

What is a capacitor?

A capacitor is an electronic component that can store electrical energy. It consists of two conductive surfaces, also known as plates, which are separated from each other by a non-conductive material, the dielectric. This structure enables the capacitor to store electrical charges.

Structure of a capacitor

A capacitor consists of two parallel metal plates separated by a dielectric. If you apply a voltage to the plates, they become charged with opposite signs - one positive, the other negative. This charge storage is the basis for the function of a capacitor.

How does a capacitor work?

Basic principle

A capacitor stores electrical energy by building up a charge when a voltage is applied to the two plates. The ability to release this energy quickly makes capacitors particularly useful in circuits that require rapid energy discharges.

Capacitance

The capacitance of a capacitor, measured in farads (F), indicates how much electrical charge it can store at a given voltage. It depends on the size of the plates, the distance between them and the dielectric. The larger the plate area and the smaller the distance, the greater the capacitance. Different dielectric materials also influence the capacitance due to their different permittivities.

Types of capacitors

Electrolytic capacitors

Electrolytic capacitors offer very high capacitance and consist of a thin oxide layer as a dielectric and a liquid or solid electrolyte. These capacitors often have a high capacitance but are usually larger and more sensitive to high voltages. They are polarised, which means that they must be connected correctly to a voltage source to avoid damage.

Ceramic capacitors

Ceramic capacitors are usually smaller and offer good temperature stability and a low capacitance tolerance. They are made of ceramic materials as a dielectric and are non-polarised, which means that they can be installed in a circuit in any direction. These capacitors are ideal for applications that require a stable capacitance.

Applications of capacitors

Energy storage: Capacitors can store and release energy quickly, making them ideal for flash units or emergency power supplies.

Interference suppression: They filter unwanted interference from electrical signals, smooth out voltage fluctuations and thus ensure stable voltages in power supply units.

Coupling and decoupling: In audio and radio circuits, capacitors separate direct current components from alternating current signals.

Time control: In time-controlled circuits, such as flashing lights, capacitors determine the time constants together with resistors.

Practical application

In practice, capacitors are often part of filter circuits that minimise interference in power supplies. They are also used to stabilise the power supply of integrated circuits by compensating for voltage drops.

Symbol and measurement

Capacitor symbol

In circuit diagrams, a capacitor is represented by two parallel lines symbolising the dielectric between the two plates. Depending on the type, the symbol may vary, for example with a plus and minus sign for polarised electrolytic capacitors.

Measuring a capacitor

To measure the capacitance of a capacitor, you will need a multimeter with a capacitance measurement function. Connect the test leads to the capacitor terminals and read the capacitance value on the multimeter display.

Frequently asked questions about capacitors

What does a capacitor do in a motor?

Starting capacitors are used to help electric motors start by providing the necessary amount of energy. These capacitors store and deliver the energy quickly, making it easier to start the motor.

How to choose a capacitor for a power supply circuit?

Choosing the right capacitor depends on the specific application. For most microcontrollers, local electrolytic capacitors of 10 µF are sufficient. For powerful audio amplifiers, larger capacitors with capacitances of several thousand microfarads are required.

Conclusion

Capacitors are indispensable components in electrical engineering. They store energy, filter signals, and stabilise voltages. With their simple structure and wide range of applications, they are a central element in many electronic circuits. Now that you know how a capacitor works, how it is constructed and where you can use it, you are well equipped to start your next electronics project!

If you're looking for high-quality capacitors, check out BerryBase. There you will find a large selection of capacitors for every project. I hope this article has given you a clear and understandable introduction to the world of capacitors. Happy making!