Knowles Voltronics P3C Trimmer Capacitor Equivalent & Substitute Parts

Part Overview

The Knowles Voltronics P3C is a 0.6–2.5pF trimmer capacitor rated for 500V operation with side adjustment and through-hole mounting. This component features a sapphire dielectric and sealed construction, designed for precision tuning applications requiring high voltage performance. The product is classified as obsolete, necessitating identification of functionally equivalent alternatives for ongoing system support and new design implementations.

Substiute Parts

P3C

Knowles VoltronicsIn Stock: 832P3C Datasheet

Current PartRFQ

GNR2R550

Sprague-GoodmanIn Stock: 945GNR2R550 Datasheet

DirectRFQ

27284

Knowles Johanson ManufacturingIn Stock: 116727284 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the P3C is determined by the following critical parameters:

• Capacitance Range Overlap: Substitute parts must cover or encompass the 0.6–2.5pF range
• Voltage Rating: Minimum 500V rating required
• Dielectric Material: Sapphire dielectric preferred for performance consistency
• Operating Temperature: Must support –55°C to 125°C range
• Adjustment Type & Mounting: Physical and functional compatibility with side adjustment mechanism

The identified substitutes are grouped as follows:

Direct Functional Equivalent (Different Mounting): Sprague-Goodman GNR2R550 provides capacitance range 0.4–2.5pF with 500V rating and sapphire dielectric, with user-defined mounting configuration.

Manufacturer-Recommended Alternative (Active Product): Knowles Johanson Manufacturing 27284 (Giga-Trim® series) offers 0.4–2.5pF capacitance with 500V operation and side adjustment, available in surface-mount configuration with active product status and RoHS compliance.

Parameter Comparison

Engineering Selection Recommendations

For Through-Hole PCB Designs: The P3C is directly replaceable by the Sprague-Goodman GNR2R550 when mounting configuration permits user-defined implementation. Both components share sapphire dielectric construction, identical voltage rating, and matching operating temperature range. The GNR2R550 extends the lower capacitance limit to 0.4pF, providing additional tuning flexibility. Q factor differential (3000 vs. 4000 @ 250MHz) should be evaluated for high-frequency applications.

For New Designs and Long-Term Availability: The Knowles Johanson Manufacturing 27284 (Giga-Trim® series) is the manufacturer-recommended active alternative. This component maintains 500V rating and side adjustment capability with confirmed RoHS compliance and active product status, ensuring sustained supply chain availability. Surface-mount configuration requires PCB redesign but provides modern manufacturing compatibility and MSL 1 moisture sensitivity rating.

Compliance Considerations: Both substitute parts carry EAR99 export classification and HTSUS code 8532.30.0090, matching the original component's regulatory profile.

Frequently Asked Questions (FAQ)

Q: Can the GNR2R550 directly replace the P3C in existing through-hole designs?

A: The GNR2R550 provides electrical equivalence (500V, sapphire dielectric, –55°C to 125°C operation) and capacitance range compatibility (0.4–2.5pF encompasses the P3C's 0.6–2.5pF range). Physical diameter matches at 0.118" (3.00mm) versus 0.140" (4.66mm) for the P3C. Mounting configuration is user-defined, requiring verification of PCB footprint compatibility and adjustment mechanism accessibility.

Q: What is the primary difference between the GNR2R550 and 27284 substitutes?

A: The GNR2R550 maintains through-hole or user-defined mounting suitable for legacy PCB designs, while the 27284 is surface-mount only. The 27284 offers active product status and RoHS compliance certification, providing superior long-term availability. The GNR2R550 retains sapphire dielectric specification; the 27284's dielectric material is not specified in available documentation.

Q: Does the 27284 surface-mount alternative require PCB redesign?

A: Yes. The 27284 is surface-mount only, whereas the P3C is through-hole. Adoption requires PCB layout modification, footprint redesign, and assembly process changes. This alternative is recommended for new product development rather than retrofit applications.

Q: Are there voltage or temperature derating considerations when substituting?

A: All identified substitutes maintain the 500V rating and –55°C to 125°C operating range of the original P3C. No derating is required based on these parameters. Q factor performance differs (GNR2R550 at 3000 @ 250MHz versus P3C at 4000 @ 250MHz); high-frequency circuit performance should be validated.

Q: What is the capacitance range difference, and does it affect compatibility?

A: The P3C operates 0.6–2.5pF; both substitutes operate 0.4–2.5pF. The extended lower range (0.4pF) in substitutes provides additional tuning capability without restricting the original operating window. Applications requiring minimum 0.6pF operation remain fully compatible.

Q: Are export restrictions different between the main part and substitutes?

A: No. All three components (P3C, GNR2R550, 27284) carry identical EAR99 export classification and HTSUS code 8532.30.0090, ensuring consistent regulatory treatment.