EM4HV Trimmer Capacitor Equivalent & Substitute Parts

Part Overview

The EM4HV is a 1–4pF trimmer capacitor rated for 1000V operation with top-surface adjustment, designed for high-voltage applications requiring precision capacitance tuning. Manufactured by Knowles Voltronics, this component features PTFE dielectric material and surface mount packaging. The EM4HV is classified as obsolete, making identification of compatible substitute parts essential for ongoing system support and new design implementations where equivalent performance is required.

Substiute Parts

EM4HV

Knowles VoltronicsIn Stock: 703EM4HV Datasheet

Current PartRFQ

AM4HV

Knowles VoltronicsIn Stock: 814AM4HV Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the EM4HV is determined by strict equivalence across the following critical parameters:

• Capacitance Range: Must match 1–4pF specification
• Voltage Rating: Must maintain 1000V minimum rating
• Adjustment Type: Must be top-adjustment configuration
• Dielectric Material: Must be PTFE for electrical performance consistency
• Q Factor: Must meet or exceed 2000 @ 100MHz
• Mounting Type: Must be surface mount compatible
• Operating Temperature: Must support –65°C to 125°C range
• Manufacturer: Knowles Voltronics maintains design and performance standards

The AM4HV qualifies as a direct substitute based on full alignment with these parameters. Physical dimension variations (diameter: 0.250" vs. 0.300") do not affect electrical equivalence but require PCB layout verification.

Parameter Comparison

Engineering Selection Recommendations

The AM4HV is the direct electrical equivalent of the EM4HV and is recommended for all applications requiring 1–4pF trimmer capacitor functionality at 1000V with top adjustment. The AM4HV offers the advantage of active product status, ensuring continued availability and manufacturing support.

The primary design consideration is the reduced diameter of the AM4HV (0.250" vs. 0.300"). This dimensional change requires verification of PCB footprint compatibility and mechanical clearance in the target assembly. Electrical performance, including capacitance range, voltage rating, Q factor, and temperature stability, remains identical.

The AM4HV carries ROHS3 compliance and REACH unaffected status, providing additional regulatory alignment for modern applications.

Frequently Asked Questions (FAQ)

Q: Can the AM4HV directly replace the EM4HV in existing designs?

A: Electrical substitution is direct. The AM4HV matches all critical electrical parameters. Physical layout verification is required due to the 0.050" diameter reduction.

Q: What is the significance of the product status change from Obsolete to Active?

A: The AM4HV is in active production, ensuring long-term availability, consistent manufacturing quality, and continued technical support from Knowles Voltronics.

Q: Are there any compliance differences between the two parts?

A: The AM4HV includes ROHS3 compliance and REACH unaffected status. Both parts maintain EAR99 export classification and identical moisture sensitivity levels.

Q: Does the smaller diameter affect electrical performance?

A: No. The diameter reduction does not alter capacitance range, voltage rating, Q factor, or temperature stability. PCB layout and mechanical clearance must be evaluated independently.

Q: What parameters must remain constant for substitution validity?

A: Capacitance range (1–4pF), voltage rating (1000V), adjustment type (top), dielectric material (PTFE), Q factor (2000 @ 100MHz), and operating temperature range (–65°C to 125°C) must all be maintained.