INDUSTRY COMPONENT

X-Capacitor

X-Capacitor is a safety-rated capacitor used in EMI filters to suppress differential-mode interference across power lines.

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Component Specifications

Definition
An X-Capacitor is a specialized film or ceramic capacitor designed for across-the-line applications in EMI/RFI filters. It is safety-certified to withstand high-voltage transients and prevent short-circuit failures that could cause fire or electric shock. Positioned between line and neutral conductors, it attenuates differential-mode noise by providing a low-impedance path for high-frequency interference while blocking mains frequency. Rated for continuous operation at mains voltages (typically 250VAC to 310VAC) with impulse withstand voltages up to several kilovolts.
Working Principle
Operates by shunting high-frequency differential-mode noise (between line and neutral) to ground or neutralizing it through capacitive reactance (Xc = 1/(2πfC)). At high frequencies, the capacitor's low impedance diverts interference away from sensitive circuits, while at mains frequency (50/60Hz), its high impedance prevents excessive current flow. Self-healing metallized film construction allows recovery from minor dielectric breakdowns.
Materials
Metallized polypropylene film (MKP) or ceramic dielectric (Class X1/Y2). Electrodes: vacuum-deposited aluminum/zinc. Encapsulation: Flame-retardant epoxy resin (UL94 V-0 rated). Leads: tinned copper wire. Optional: internal fuse protection.
Technical Parameters
  • Tolerance ±10% to ±20%
  • Capacitance 100pF to 10μF
  • Safety Class X1 (high impulse), X2 (standard)
  • Rated Voltage 250VAC to 310VAC
  • Impulse Voltage 2.5kV to 4kV (X1), ≤1.2kV (X2)
  • Temperature Range -40°C to +110°C
  • Dissipation Factor <0.001 at 10kHz
  • Insulation Resistance ≥10,000 MΩ
Standards
IEC 60384-14, UL 60384-14, EN 60384-14, GB/T 6346

Industry Taxonomies & Aliases

Commonly used trade names and technical identifiers for X-Capacitor.

X capacitor EMI filter capacitor safety capacitor differential-mode filter X1/X2 class metallized polypropylene capacitor power line filter X-Capacitor X-Capacitor in Electrical Equipment Manufacturing

Parent Products

This component is used in the following industrial products

EMI Filter

A passive electronic component designed to suppress electromagnetic interference (EMI) in industrial electrical systems.

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Power Line Filter(s)

Electrical component that suppresses electromagnetic interference (EMI) and radio frequency interference (RFI) from power lines

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Engineering Analysis

Risks & Mitigation
  • Dielectric breakdown from voltage surges
  • Fire hazard if non-safety-rated capacitor used
  • Leakage current exceeding limits
  • Thermal runaway at high temperatures
  • Mechanical damage cracking dielectric
FMEA Triads
Trigger: Overvoltage transients exceeding rated impulse voltage
Failure: Dielectric puncture leading to short circuit
Mitigation: Use X1 class for high-surge environments; incorporate varistors or gas discharge tubes for surge suppression
Trigger: Excessive ripple current causing internal heating
Failure: Thermal degradation of dielectric, capacitance drift
Mitigation: Select capacitors with adequate ripple current rating; ensure proper ventilation in filter assembly
Trigger: Moisture ingress due to poor encapsulation
Failure: Reduced insulation resistance, leakage current increase
Mitigation: Use epoxy-encapsulated versions for humid environments; conformal coating on PCB

Industrial Ecosystem

Compatible With

Interchangeable Parts

Compliance & Inspection

Tolerance
Capacitance tolerance ±10% to ±20%; impulse test per IEC 60384-14
Test Method
High-potential test (2U+1000VAC for 60s); impulse voltage test (specified pulses); flammability test (UL94); endurance test (1000h at rated voltage)

Buyer Feedback

★★★★☆ 4.8 / 5.0 (16 reviews)

"Great transparency on the X-Capacitor components. Essential for our Electrical Equipment Manufacturing supply chain."

"The X-Capacitor we sourced perfectly fits our Electrical Equipment Manufacturing production line requirements."

"Found 44+ suppliers for X-Capacitor on CNFX, but this spec remains the most cost-effective."

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Frequently Asked Questions

What is the difference between X1 and X2 class capacitors?

X1 capacitors withstand higher impulse voltages (≥2.5kV) for industrial applications with severe transients. X2 capacitors (≤1.2kV impulse) are for general-purpose equipment with moderate transients.

Can X-Capacitors be used without safety certifications?

No. Using uncertified capacitors in across-the-line positions violates safety regulations (IEC/UL) and risks fire from dielectric breakdown during voltage surges.

How do X-Capacitors differ from Y-Capacitors?

X-Capacitors are placed line-to-neutral for differential-mode noise. Y-Capacitors are line-to-ground or neutral-to-ground for common-mode noise and require higher safety isolation.

Can I contact factories directly?

Yes, each factory profile provides direct contact information.

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