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Definition of capacitor

Capacitors are components that store electricity and electrical energy (electrical potential energy). A conductor system in which one conductor is surrounded by another conductor, or in which the electric field lines emitted by one conductor all terminate in another conductor, is called a capacitor.

The role of capacitors

In a DC circuit, the capacitor is equivalent to a broken circuit. Capacitor is a component that can store electric charge and is one of the most commonly used electronic components.

At their core, they store and release electrical energy, making them essential for filtering, decoupling, and stabilizing power supplies in electronic circuits. Capacitors facilitate signal coupling and precise timing in amplifiers and oscillators. In applications like electric motors and energy conservation, they assist in starting and storing energy efficiently. These components also enable memory backup, manual tuning, and power factor correction. Moreover, advanced supercapacitors hold promise in emerging energy storage solutions.

How to choose a suitable capacitor

At Nantian Electronics, we are proud to be your premier destination for high-quality capacitors. With a commitment to excellence and a track record of reliability, we offer a wide range of capacitors to meet the diverse needs of our customers. Here's why you should choose Nantian Electronics as your capacitor supplier.

1. Choose the right model

Generally used in circuits for low-frequency coupling, bypass decoupling, etc., paper capacitors, electrolytic capacitors, etc. are used when electrical performance requirements are not strict. For the coupling capacitor of the low-frequency amplifier, choose an electrolytic capacitor of 1-22μF. The bypass capacitor is selected according to the operating frequency of the circuit. For example, in a low-frequency circuit, the transmitting bypass capacitor is an electrolytic capacitor with a capacity between 10 and 220 μF. In an intermediate frequency circuit, paper and film capacitors of 0.01 to 0.1 μF can be used; In high-frequency circuits, mica capacitors and porcelain capacitors should be used. In power supply filtering and decoupling circuits, electrolytic capacitors can be used. In these situations, the requirements for capacitors are not high, as long as the volume allows and the capacity is sufficient.

2. Reasonably select the accuracy of capacitors

In bypass, decoupling, and low-frequency coupling circuits, if there are no strict requirements on the accuracy of capacitors, capacitors with similar or slightly larger capacities can be selected based on the design values.

But in other circuits, such as oscillation loops, delay loops, and tone control circuits, the capacitance of the capacitor needs to be as consistent as possible with the calculated value. Among various filters, there are higher requirements for the accuracy of capacitance, and high-precision capacitors should be selected.

3. Determine the rated working voltage of the capacitor

The rated operating voltage of the capacitor should be higher than the actual operating voltage, with sufficient margin to prevent damage due to voltage fluctuations. Generally speaking, the working voltage should be 10% to 20% lower than the rated working voltage of the capacitor. In some circuits, the voltage fluctuations are larger and a larger margin can be left.

Generally, small-capacity capacitors have very little dielectric loss, and have better temperature resistance and stability. However, the circuit requirements for them are often relatively high, so there should still be a certain margin when selecting the rated operating voltage, and attention should also be paid to the environment. Effect of operating temperature.

4. Try to use capacitors with large insulation resistance

The smaller the insulation resistance of the capacitor, the greater the leakage current. The leakage current not only consumes the power in the circuit, but more importantly, it can cause the circuit to malfunction or reduce the performance of the circuit. The power loss caused by leakage current will cause the capacitor to heat up, and as its temperature rises, a greater leakage current will be generated. This cycle can easily damage the capacitor. Therefore, when selecting capacitors, capacitors with sufficiently high insulation resistance should be selected, especially capacitors used under high temperature and high pressure conditions.

5. Consider temperature coefficient and frequency characteristics

The larger the temperature coefficient of the capacitor, the greater the change in its capacity with temperature, which is not allowed in many circuits. For example, the oscillation circuit components, phase-shifting network components, filters, etc. in the oscillation circuit have large temperature coefficients, which will cause the circuit to drift and cause the circuit to operate unstable. In these situations, capacitors with small temperature coefficients should be selected to ensure stable operation.

6. Pay attention to the usage environment

The quality of the use environment directly affects the performance and life of the capacitor. In an environment with high operating temperature, capacitors are prone to leakage and accelerated aging. Therefore, when designing and installing, use capacitors with small temperature coefficients as much as possible, keep them away from heat sources and improve ventilation and heat dissipation inside the machine. If necessary, forced air cooling should be used. Under cold conditions, due to very low temperatures, ordinary electrolytic capacitors will fail due to freezing of the electrolyte, causing the equipment to work abnormally. Therefore, cold-resistant electrolytic capacitors must be used. When working under windy and sandy conditions or in an environment with high humidity, sealed capacitors should be used to improve the dust-proof and moisture-proof performance of the equipment.

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