Rotor Plates: Capacitance Range 5-500pF, Diameter 10-100mm

Q: What is the primary function of rotor plates in variable capacitors?

Rotor plates serve as the movable electrodes that change overlap area with stator plates to adjust capacitance values in electronic circuits.

Q: How do material choices affect rotor plate performance?

Material selection impacts conductivity, weight, corrosion resistance, and thermal stability. Aluminum offers light weight, brass provides good machinability, while copper offers superior conductivity.

Q: What maintenance do rotor plates require?

Regular cleaning to remove oxidation, lubrication of rotation mechanisms, and inspection for physical deformation or wear at contact points.

Component Specifications

Definition

Rotor plates are precision-engineered metallic components that form the moving electrode assembly in variable capacitors. They rotate on a central shaft to vary the effective overlapping surface area with stationary stator plates, thereby enabling precise capacitance adjustment. These plates are typically arranged in a semi-circular or segmented pattern to provide linear or logarithmic capacitance variation.

Working Principle

Rotor plates operate on the principle of variable parallel-plate capacitance. As the rotor rotates, the overlapping area between rotor and stator plates changes, altering the capacitance according to the formula C = εA/d, where ε is permittivity, A is overlap area, and d is plate separation. This mechanical movement allows for continuous capacitance tuning in electronic circuits.

Materials

Aluminum alloy (6061-T6), Brass (C36000), Copper (C11000), or Silver-plated steel; Thickness: 0.3-1.2mm; Surface finish: Electropolished or anodized for corrosion resistance

Technical Parameters

Parameter	Typical range	Notes & selection driver
Diameter	10-100mm
Thickness	0.3-1.2mm
Plate Count	2-20 plates
Rotation Angle	180-270 degrees
Maximum Voltage	250-1000V DC
Capacitance Range	5-500pF
Temperature Range	-40°C to +85°C
Contact Resistance	<10mΩ

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 60384-1, DIN 41494

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 at high voltage
Mechanical wear from repeated rotation
Corrosion affecting conductivity
Resonance at specific frequencies
Thermal expansion misalignment

FMEA Triads

Trigger: Material fatigue from repeated rotational stress
Failure: Crack formation leading to mechanical failure
Mitigation: Use fatigue-resistant alloys and implement stress relief design features

Trigger: Oxidation buildup on contact surfaces
Failure: Increased contact resistance and signal loss
Mitigation: Apply protective coatings and specify regular maintenance schedules

Trigger: Thermal expansion mismatch between materials
Failure: Plate warping and capacitance drift
Mitigation: Select materials with similar thermal coefficients and design expansion allowances

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

±5% capacitance variation, ±0.1mm dimensional tolerance, ±2° angular positioning accuracy

Test Method

Capacitance measurement per IEC 60384-1, dielectric withstand voltage test, rotational torque measurement, environmental testing per MIL-STD-202

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 Rotor Plates

Manufacturer profiles associated with Rotor Plates.

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Frequently Asked Questions

What is the primary function of rotor plates in variable capacitors?