Capacitors

Capacitors are passive electrical components found in almost all electronics applications. Our range includes over 60,000 different capacitors, including aluminium, tantalum, polymer, polyester film, and ceramic capacitors. We source from globally renowned manufacturers like AVX, Murata, KEMET, Panasonic, TDK and many more, so that you can rely on exceptional performance and quality.

What is a Capacitor and What Does It Do?

A capacitor is an electrical component that stores energy in an electric field. It functions similarly to a battery, but with the ability to release its stored charge much faster. The amount of energy a capacitor can store is known as its capacitance, measured in Farads (F).

Capacitors are constructed with two conductive metal plates (electrodes) separated by an insulating material called a dielectric. When a voltage is applied across the plates, an electric field is created, and opposite charges accumulate on each plate, storing electrical energy.

Capacitor Types and Their Specifications

Various capacitor types exist, each with unique properties and specifications tailored to specific applications. The choice of materials for the metal plates and dielectric significantly influences the capacitor's characteristics. Key factors to consider when selecting a capacitor include:

Aluminium Capacitors

• Construction: Aluminium electrolytic capacitors consist of two aluminium foils separated by a paper dielectric saturated with an electrolyte.
• Advantages: High capacitance values, low cost, and wide availability.
• Disadvantages: Polarised (must be connected with correct polarity), relatively high leakage current, and limited lifespan.
• Applications: Power supplies, audio amplifiers, and other applications requiring high capacitance values.

Tantalum Capacitors

• Construction: Tantalum capacitors use a tantalum metal anode, a manganese dioxide cathode, and a solid or liquid electrolyte.
• Advantages: High capacitance density, low leakage current, and long lifespan.
• Disadvantages: Polarised, sensitive to voltage spikes, and relatively expensive.
• Applications: Compact electronic devices, mobile phones, laptops, and medical equipment.

Polymer Capacitors

• Construction: Polymer capacitors are similar to tantalum capacitors but use a conductive polymer electrolyte.
• Advantages: Lower ESR (equivalent series resistance) than tantalum capacitors, improved stability, and higher ripple current capability.
• Disadvantages: Polarised and slightly more expensive than tantalum capacitors.
• Applications: High-frequency applications, DC-DC converters, and motherboards.

Polyester Film Capacitors

• Construction: Polyester film capacitors use a thin polyester film dielectric sandwiched between two metallised electrodes.
• Advantages: Non-polarised, stable capacitance values, and low leakage current.
• Disadvantages: Lower capacitance values than electrolytic capacitors and larger physical size.
• Applications: Audio circuits, timing circuits, and coupling applications.

Ceramic Capacitors

• Construction: Ceramic capacitors use a ceramic dielectric material between two metal electrodes.
• Advantages: Non-polarised, very low ESR, and high-frequency performance.
• Disadvantages: Lower capacitance values than electrolytic capacitors and can be sensitive to mechanical stress.
• Applications: High-frequency circuits, decoupling, and bypass applications.

Advantages of Using Capacitors

Capacitors are essential components in electronics due to their unique capabilities:

• Energy Storage and Release: Capacitors can store electrical energy and release it quickly, making them ideal for applications like camera flashes, power supplies, and pulsed power systems.
• Filtering: Capacitors can filter out unwanted frequencies from electrical signals, allowing for smooth and clean power delivery or signal transmission.
• DC Blocking: Capacitors block DC current while allowing AC signals to pass, making them useful in coupling and decoupling applications.
• Timing and Oscillation: Capacitors, in combination with resistors or inductors, can create timing circuits and oscillators, generating precise frequencies and time intervals.
• Voltage Regulation: Capacitors can help stabilise voltage levels in power supplies and other circuits, ensuring consistent performance.
• Power Factor Correction: In industrial applications, capacitors are used to improve power factor, reducing energy consumption and improving efficiency.

Industrial Capacitors Applications

Capacitors are essential components in diverse industrial settings, ensuring efficient and reliable power management.

• Discrete Manufacturing: Capacitors filter and smooth power supplies, enable precise timing and control, and store energy for pulsed applications in machinery and automation systems.
• Process Manufacturing: They improve power factor, filter noise in instrumentation, and provide backup power for process control and safety in industries like chemical processing and food production.
• Energy & Utilities: Capacitors optimise power grids through power factor correction, filter harmonics in power electronics, and store energy for renewable energy systems.
• Facilities & Intralogistics: They enhance power efficiency, filter noise in lighting and HVAC, and provide backup power for critical infrastructure in buildings and warehouses.

How to Choose the Right Capacitor

Selecting the right capacitor involves considering several key factors:

• Capacitance Value: The capacitance value, measured in Farads, determines the amount of electrical energy the capacitor can store. Choose a capacitor with a capacitance value that matches your application's requirements.
• Voltage Rating: The voltage rating specifies the maximum voltage the capacitor can safely handle. Exceeding this rating can lead to component failure or even safety hazards.
• Tolerance: The tolerance indicates the allowable deviation from the specific capacitance value. Choose a capacitor with a tolerance that suits your application's precision needs.
• Temperature Range: The operating temperature range of the capacitor is crucial, especially for applications in harsh environments. Ensure the capacitor can withstand the temperature fluctuations it will be exposed to.
• ESR (Equivalent Series Resistance): ESR represents the internal resistance of the capacitor, affecting its performance in high-frequency applications. Choose a capacitor with low ESR for optimal efficiency.
• Size and Mounting Type: Consider the physical size and mounting type of the capacitor to ensure compatibility with your circuit board or equipment.
• IP Rating: If your application involves exposure to dust or moisture, select a capacitor with an appropriate IP rating to ensure protection and reliability.

Trusted Capacitor Manufacturer, Supplier & Distributor in Australia

RS is a leading supplier and distributor of capacitors and other related products in Australia. We offer a vast selection of high-quality capacitors from renowned brands like AVX, Murata, KEMET, Panasonic, and TDK, catering to a wide range of industrial and electronic applications. Browse our extensive online catalogue to find the perfect capacitor for your needs.

Buy Capacitors from RS

RS Australia offers swift delivery of capacitors and other passive components like potentiometers. For more details on delivery services and fees, please refer to our Delivery page.