Top 10 Capacitor Brand & Manufacturers

What is a Capacitor?

A capacitor is a passive two - terminal electrical component that stores energy in an electric field. It consists of two conductive plates separated by a dielectric material. When a voltage is applied across the capacitor, positive and negative charges accumulate on the two plates respectively, creating an electric field between them. The ability of a capacitor to store charge is quantified by its capacitance.

History of Capacitor

• Early Developments: The concept of capacitance dates back to the 18th century. In 1745, Ewald Georg von Kleist and Pieter van Musschenbroek independently invented the Leyden jar, which was an early form of capacitor. The Leyden jar consisted of a glass jar filled with water and a metal rod inserted through a stopper. It was used to store static electricity and conduct early electrical experiments.
• Technological Advancements: As the understanding of electricity grew, so did the development of capacitors. The use of different dielectric materials such as mica, paper, and later plastics and ceramics became more prevalent. The invention of the electrolytic capacitor in the late 19th and early 20th centuries was a significant milestone. It allowed for the creation of capacitors with much higher capacitance values compared to previous designs.
• Modern Developments: In modern times, capacitors have become highly specialized. Miniaturization techniques have led to the production of extremely small surface - mount capacitors used in electronics such as smartphones and laptops. Additionally, new dielectric materials and manufacturing processes have enabled the development of capacitors with high - energy storage capabilities, high - frequency performance, and improved reliability for applications ranging from power electronics to telecommunications.

Purpose of Capacitor

• Energy Storage: Capacitors are used to store electrical energy. In applications such as camera flashes, the energy stored in a capacitor is quickly released to produce a bright flash. In power - electronics circuits, capacitors store energy during one part of a cycle and release it during another to smooth out voltage and current waveforms.
• Filtering: In electronic circuits, capacitors are used as filters. In a power - supply circuit, for example, a capacitor can act as a filter to remove the AC ripple from a rectified DC output. In audio - frequency circuits, capacitors are used to separate different frequency components, allowing only the desired frequencies to pass through.
• Coupling and Decoupling: Capacitors are used to couple or decouple different parts of an electronic circuit. In a coupling application, a capacitor allows the AC signal to pass from one stage of a circuit to another while blocking the DC component. In a decoupling application, a capacitor provides a local energy - storage reservoir to prevent electrical noise from one part of a circuit from affecting other parts.
• Tuning: In radio - frequency (RF) circuits, capacitors are used for tuning. By changing the capacitance value (for example, using a variable capacitor), the resonant frequency of an LC circuit (consisting of an inductor and a capacitor) can be adjusted. This is used in radio receivers to select different frequencies.

Principle of Capacitor

• Capacitance and Charge Storage: The capacitance $C$ of a capacitor is given by the formula $C = frac{epsilon A}{d}$, where $epsilon$ is the permittivity of the dielectric material, $A$ is the area of the conductive plates, and $d$ is the distance between the plates. When a voltage $V$ is applied across the capacitor, the charge $Q$ stored on the capacitor is related to the capacitance and voltage by $Q = CV$. The energy $W$ stored in the capacitor is given by $W=frac{1}{2}CV^{2}$. As the voltage across the capacitor changes, the charge on the plates also changes, following the relationship $I = Cfrac{dV}{dt}$, where $I$ is the current flowing into or out of the capacitor.
• Dielectric Function: The dielectric material between the capacitor plates serves several important functions. It increases the capacitance by allowing a higher electric field to be established for a given voltage. It also provides electrical insulation between the plates, preventing a direct flow of current between them. Different dielectric materials have different permittivity values, which affect the capacitance, and different breakdown voltages, which determine the maximum voltage the capacitor can withstand.

Features of Capacitor

• Capacitance Value: Capacitors come in a wide range of capacitance values, from a few picofarads ($pF$) to several farads ($F$). The capacitance value determines the amount of charge the capacitor can store and its behavior in a circuit. For example, a small - capacitance capacitor may be used for high - frequency filtering, while a large - capacitance capacitor is used for energy storage or low - frequency applications.[!--empirenews.page--]
• Voltage Rating: Each capacitor has a maximum voltage rating. Exceeding this voltage can lead to dielectric breakdown, which causes the capacitor to short - circuit. The voltage rating depends on the dielectric material and the physical construction of the capacitor. It is important to select a capacitor with a voltage rating that is suitable for the operating voltage of the circuit.
• Tolerance: Capacitors have a tolerance value that indicates the allowable deviation from the nominal capacitance value. For example, a capacitor with a 10% tolerance may have an actual capacitance that is within 10% of the stated value. The tolerance affects the precision of the circuit's operation, especially in applications where the exact capacitance value is critical.
• Equivalent Series Resistance (ESR): In real - world capacitors, there is an equivalent series resistance. ESR represents the internal resistance of the capacitor and affects its performance. A high - ESR capacitor can cause energy losses and affect the filtering and energy - storage capabilities of the capacitor. Capacitors with low ESR are preferred in applications where efficiency is important.
• Temperature Coefficient: The capacitance of a capacitor can change with temperature. The temperature coefficient indicates how much the capacitance changes per degree of temperature change. In some applications, such as in temperature - sensitive circuits, it is important to consider the temperature coefficient to ensure stable circuit performance.

Types of Capacitor

• Film Capacitors: These capacitors use a thin plastic film as the dielectric. They have a wide range of capacitance values and good stability. Film capacitors include polyester, polypropylene, and polystyrene capacitors. They are used in applications such as power - supply filtering, audio - frequency circuits, and some RF applications.
• Ceramic Capacitors: Ceramic capacitors have a ceramic material as the dielectric. They can have a very high capacitance - to - volume ratio and are available in small sizes. However, their capacitance can vary with voltage and temperature. They are widely used in high - frequency circuits, such as in RF and microwave applications, and in decoupling applications in digital electronics.
• Electrolytic Capacitors: These capacitors have a polarized construction, with an electrolyte and a metal oxide as the dielectric. They can have very high capacitance values, making them useful for applications where a large amount of energy storage is needed. However, they have a polarity, and incorrect polarity connection can lead to damage or failure. They are commonly used in power - supply circuits and audio - amplifier circuits.
• Tantalum Capacitors: Tantalum capacitors are a type of electrolytic capacitor. They have a tantalum - based anode and a solid electrolyte. They offer high - capacitance values in a relatively small size and have good stability and low - leakage current. They are often used in portable electronics and applications where space is limited.
• Variable Capacitors: These capacitors have a mechanism to change their capacitance value. They are used in applications such as radio - tuning circuits, where the capacitance needs to be adjusted to select different frequencies. Variable capacitors can be mechanically or electrically adjustable.

Precautions for using Capacitor

• Over - Voltage Protection: Ensure that the voltage applied across the capacitor does not exceed its rated voltage. Over - voltage can lead to dielectric breakdown and capacitor failure. In circuits with voltage spikes or surges, use appropriate protection devices such as varistors or transient - voltage - suppression diodes.
• Polarity (for Polarized Capacitors): If using electrolytic or tantalum capacitors, pay close attention to the polarity. Connecting these capacitors with the wrong polarity can cause damage, including leakage, short - circuit, or even explosion. Always follow the manufacturer's instructions regarding polarity.
• ESR and Power Dissipation: Consider the equivalent series resistance (ESR) of the capacitor. High - ESR capacitors can dissipate more power as heat, which can affect the capacitor's lifespan and performance. In high - power applications, choose capacitors with low ESR to minimize power losses.
• Temperature Considerations: Be aware of the temperature limitations of the capacitor. Extreme temperatures can affect the capacitance value, the dielectric strength, and the overall performance of the capacitor. In applications where the temperature may vary, select a capacitor with an appropriate temperature coefficient and ensure proper heat - dissipation if necessary.
• Leakage Current: Capacitors, especially electrolytic capacitors, have a small leakage current. Excessive leakage current can cause problems in some applications, such as in battery - powered devices. When selecting a capacitor, consider the leakage - current specification and ensure it is within an acceptable range for the application.[!--empirenews.page--]

Things to consider when purchasing Capacitor

• Application Requirements: Determine the specific requirements of the application. Consider the capacitance value, voltage rating, frequency range, and the need for energy storage, filtering, or coupling. For example, if you are designing a high - frequency RF circuit, you may need a ceramic capacitor with a specific capacitance value and low - loss characteristics at high frequencies.
• Type of Capacitor: Based on the application, select the appropriate type of capacitor. Each type has its own advantages and disadvantages in terms of capacitance range, voltage rating, stability, and other characteristics. For example, for a power - supply filtering application, a film capacitor or an electrolytic capacitor may be suitable, depending on the specific requirements.
• Performance Characteristics: Look at the capacitance tolerance, voltage rating, ESR, temperature coefficient, and leakage current. The capacitance tolerance should meet the precision requirements of the circuit. The voltage rating should be sufficient to handle the operating voltage. A low ESR and an appropriate temperature coefficient are important for efficient and stable operation. The leakage current should be within an acceptable range for the application.
• Size and Physical Dimensions: Consider the physical size of the capacitor. It should fit into the available space in your equipment or circuit board. The size of the capacitor is related to its capacitance value, voltage rating, and the type of dielectric material used. In portable electronics, small - sized capacitors are often preferred.
• Cost and Budget: Establish a budget for the capacitor purchase. The cost can vary depending on the type, performance, and brand of the capacitor. Consider not only the initial purchase price but also the long - term costs such as potential replacement due to failures and any additional costs associated with handling and installation. A more expensive capacitor with better performance and reliability may be a more cost - effective choice in the long run for some applications.
• Manufacturer Support and Training: Select a reputable manufacturer that provides good technical support and training. Operating and using a capacitor correctly may require some technical knowledge, and the manufacturer should offer resources such as user manuals, online tutorials, and customer support to help you get the most out of the device.

Terms of Capacitor

• Capacitance ($C$): A measure of the ability of a capacitor to store electrical charge. It is defined as the ratio of the charge stored on the capacitor to the voltage across it. The unit of capacitance is the farad ($F$), but in practice, picofarads ($pF$), nanofarads ($nF$), and microfarads ($mu F$) are more commonly used.
• Dielectric Constant ($epsilon_{r}$): The ratio of the permittivity of the dielectric material to the permittivity of free space. It affects the capacitance value of the capacitor. A higher dielectric constant allows for a higher capacitance for a given plate area and distance between the plates.
• Equivalent Series Resistance (ESR): A measure of the internal resistance of a capacitor. It affects the capacitor's performance in terms of power dissipation, filtering efficiency, and energy - storage capabilities.
• Tolerance: The allowable deviation from the nominal capacitance value of a capacitor. It is usually expressed as a percentage and affects the precision of the circuit's operation.
• Temperature Coefficient: A measure of how the capacitance of a capacitor changes with temperature. It is an important factor in applications where temperature stability is required.