What are the key factors in the selection criteria of AC Capacitor in different application scenarios?

In different application scenarios, the selection criteria of AC Capacitor will vary according to specific needs, but usually involve the following key factors:

CBB65-R2

1. Voltage level
Criticality: This is the most basic and important parameter. The capacitor must be able to operate safely at its rated voltage, and the voltage fluctuation range needs to be considered.
Application scenario: In power systems, such as transmission and distribution lines, capacitors need to withstand high voltages (kV level), while in electronic equipment, the voltage may be only tens of volts or even lower.
Note: The rated voltage of the capacitor should be higher than the actual operating voltage by a certain percentage (usually 10%~20%) to ensure safe operation.

2. Capacitance (capacitance value)
Criticality: The capacitance value determines the energy storage capacity and filtering effect of the capacitor in the circuit.
Application scenario: In power supply filtering, a larger capacitor is required to smooth voltage fluctuations; while in high-frequency circuits, a smaller capacitor may be required to achieve resonance or coupling functions.
Note: The accuracy of the capacitance value is also important, especially in precision circuits.

3. Frequency range
Criticality: The operating frequency range of AC capacitors directly affects their performance. The impedance, loss and equivalent series resistance (ESR) of capacitors will vary at different frequencies.
Application scenarios: In power systems, it usually works at 50Hz or 60Hz; while in electronic equipment (such as switching power supplies, communication equipment), it may be necessary to work at high frequencies (such as MHz level).
Notes: In high-frequency applications, capacitors with low ESR and low losses need to be selected to avoid excessive heat and loss.

4. Temperature range
Criticality: Temperature affects the performance and life of capacitors. The dielectric properties of capacitors change with temperature, which may cause capacity drift or failure.
Application scenarios: In industrial environments or outdoor equipment, capacitors need to work in a wide temperature range (such as -40℃~+85℃); while in indoor or consumer electronic devices, the temperature range may be narrower.
Notes: It is necessary to select the appropriate temperature grade according to the actual working environment, while considering the temperature coefficient of the capacitor.

5. Size and packaging form
Criticality: Size and packaging form determine the installation method and space occupied by the capacitor.
Application scenario: In miniaturized electronic devices (such as mobile phones and tablets), it is necessary to select miniaturized, chip-type capacitors; while in power systems, larger leaded or bolted capacitors may be required.
Notes: Miniaturized capacitors usually require higher manufacturing process and material requirements.

6. Reliability and life
Criticality: The life of the capacitor directly affects the reliability and maintenance cost of the equipment.
Application scenario: In scenarios with high reliability requirements (such as aerospace and medical equipment), it is necessary to select capacitors with high life and high reliability.
Notes: The life is closely related to the working conditions (such as temperature, voltage, and frequency) and needs to be considered comprehensively.

7. Loss and efficiency
Criticality: The loss of the capacitor (such as dielectric loss and ESR) will affect the efficiency and heating of the circuit.
Application scenario: In high-frequency circuits and high-power applications, loss is particularly important, and low-loss capacitors need to be selected.
Note: Losses are usually measured by loss tangent (tanδ) or ESR. Low-loss capacitors can reduce energy loss and heat generation.