Primary Capacitors: Temperature Range -40°C to 105°C

Q: What is the main function of a primary capacitor in a power supply unit?

The primary capacitor filters and smooths the input AC voltage, reducing ripple and providing stable DC output to protect downstream components.

Q: How do I select the right primary capacitor for my application?

Consider voltage rating, capacitance, temperature range, and ESR based on the power supply's load requirements and environmental conditions.

Component Specifications

Definition

Primary capacitors are high-capacitance electronic components used in the input stage of power supply units to store electrical energy, reduce voltage ripple, and provide stable DC output by filtering AC components. They handle high voltage and current levels, ensuring efficient power conversion and protection against electrical noise.

Working Principle

Primary capacitors operate by storing electrical charge in an electric field between two conductive plates separated by a dielectric material. In power supply units, they charge during peak voltage cycles and discharge during low cycles, smoothing out fluctuations to maintain consistent voltage output.

Materials

Aluminum electrolytic (common), film (polypropylene/polyester), ceramic (for high-frequency applications), with electrolytes (for electrolytic types) and metal electrodes.

Technical Parameters

Parameter	Typical range	Notes & selection driver
ESR	Low (e.g., <0.1Ω)
Lifetime	2000 to 10000 hours
Capacitance	100uF to 10000uF
Voltage Rating	200V to 600V
Temperature Range	-40°C to 105°C

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards

ISO 9001, IEC 60384, DIN EN 60384

Parent Products

This component is used in the following industrial products

Power Supply Units

Electronic devices that convert electrical power from a source to the correct voltage, current, and frequency required by electrical equipment.

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Engineering Analysis

Risks & Mitigation

Overheating due to high current
Electrolyte leakage
Voltage spikes causing failure
Reduced lifespan from excessive ripple current

FMEA Triads

Trigger: High ripple current
Failure: Capacitor overheating and premature failure
Mitigation: Use capacitors with higher ripple current ratings and implement thermal management.

Trigger: Voltage exceeding rating
Failure: Dielectric breakdown and short circuit
Mitigation: Select capacitors with voltage ratings above maximum operating voltage and use overvoltage protection circuits.

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

±20% for capacitance, ±10% for voltage

Test Method

IEC 60384 standards for capacitance, ESR, leakage current, and endurance testing

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

Check the legal entity, factory address, ownership, certifications, and direct contacts.

CNFX does not score or rank suppliers. Buyers must verify all claims and documents with the legal manufacturer before ordering.

Manufacturers of Primary Capacitors

Manufacturer profiles associated with Primary Capacitors.

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Compiled and source-reviewed by the CNFX editorial team. Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review

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Frequently Asked Questions

What is the main function of a primary capacitor in a power supply unit?