Dielectric: Temperature Range -55°C to +125°C

Q: What is the role of dielectric in a variable capacitor?

The dielectric separates conductive plates, stores electrostatic energy via polarization, and allows capacitance adjustment by changing plate overlap or dielectric position, enabling tuning in circuits.

Q: How does dielectric constant affect capacitor performance?

Higher dielectric constant increases capacitance for a given size, but may reduce stability or increase losses. Selection balances capacity, frequency response, and temperature stability.

Component Specifications

Definition

A dielectric is a non-conductive material that becomes polarized when subjected to an electric field, enabling energy storage in capacitors. In variable capacitors, it separates conductive plates and determines capacitance through its permittivity, thickness, and area. Dielectrics prevent electrical discharge while allowing electrostatic field formation, crucial for tuning and filtering in electronic circuits.

Working Principle

Dielectrics work by polarizing under an electric field, where molecular dipoles align to store electrostatic energy. In variable capacitors, adjusting the plate overlap area or dielectric insertion changes capacitance. The dielectric constant (relative permittivity) defines energy storage capacity, with higher values increasing capacitance. It insulates to prevent arcing while enabling reversible energy storage and release.

Materials

Common materials include ceramic (e.g., barium titanate), polymer films (e.g., polyester, polypropylene), mica, glass, or air. Specifications involve dielectric constant (εr), breakdown voltage (kV/mm), loss tangent (tan δ), temperature coefficient (ppm/°C), and moisture resistance.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Loss Tangent	<0.01 for low-loss applications
Breakdown Voltage	10-100 kV/mm
Temperature Range	-55°C to +125°C
Dielectric Constant	2-10,000 (material-dependent)
Thickness Tolerance	±5%

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

Standards

IEC 60384, ASTM D150, ISO 6721

Parent Products

This component is used in the following industrial products

Variable Capacitor

A capacitor whose capacitance can be intentionally and repeatedly changed mechanically or electronically.

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Engineering Analysis

Risks & Mitigation

Dielectric breakdown from overvoltage
Capacitance drift due to temperature/humidity
Increased losses at high frequencies

FMEA Triads

Trigger: Overvoltage exceeding breakdown strength
Failure: Dielectric breakdown, short circuit
Mitigation: Design with safety margins, use overvoltage protection circuits

Trigger: Material degradation from moisture absorption
Failure: Capacitance drift, increased leakage current
Mitigation: Use hermetic sealing, select moisture-resistant materials

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

Capacitance tolerance ±5% to ±20%, depending on application

Test Method

IEC 60384 for capacitance, loss tangent, and insulation resistance measurements

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

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Inspection readiness

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Supplier transparency

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Manufacturers of Dielectric

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Frequently Asked Questions

What is the role of dielectric in a variable capacitor?