81F20R Equivalent & Substitute Parts Reference

Part Overview

The Ohmite 81F20R is a 20 Ohm ±1% 1W axial wirewound through-hole resistor from the Acrasil® 80 series. This component is designed for applications requiring precision resistance with wirewound construction and is currently in active production status. Equivalent and substitute parts are identified based on matching electrical specifications, mechanical compatibility, and functional performance characteristics.

Substiute Parts

81F20R

OhmiteIn Stock: 120881F20R Datasheet

Current PartRFQ

RS01A20R00FS70

Vishay DaleIn Stock: 2007RS01A20R00FS70 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the 81F20R is determined by the following critical parameters:

• Resistance Value: 20 Ohms (exact match required)
• Tolerance: ±1% (precision specification)
• Power Rating: 1W (thermal capability)
• Composition: Wirewound (construction type)
• Package: Axial (mechanical form factor)
• Temperature Coefficient: ±20ppm/°C (stability specification)
• Termination Count: 2 (connection points)

The Vishay Dale RS01A20R00FS70 meets all these critical parameters and qualifies as a direct functional equivalent. Both components share identical electrical specifications and compatible mechanical packaging, enabling direct substitution in circuit applications.

Parameter Comparison

Engineering Selection Recommendations

Both the 81F20R and RS01A20R00FS70 are active production components with matching core electrical specifications. Selection between these parts should be based on:

81F20R (Ohmite Acrasil® 80): Use when the original specification calls for Ohmite series components or when standard wirewound performance is required.

RS01A20R00FS70 (Vishay Dale RS): Use as a direct substitute when moisture-resistant construction is beneficial for the application environment. This part offers a slightly smaller physical footprint (0.094" diameter vs. 0.126" diameter) while maintaining identical electrical performance. The specified operating temperature range of -65°C to 250°C provides explicit thermal boundaries for design verification.

Both components are RoHS non-compliant and share the same HTSUS classification (8533.21.0080), indicating equivalent regulatory treatment for import and export purposes.

Frequently Asked Questions (FAQ)

Q: Can RS01A20R00FS70 be used as a direct replacement for 81F20R?

A: Yes. Both components have identical resistance (20 Ohms), tolerance (±1%), power rating (1W), composition (wirewound), and temperature coefficient (±20ppm/°C). The axial package type and two-termination configuration are compatible. The RS01A20R00FS70 has a smaller physical diameter (0.094" vs. 0.126"), which may require PCB layout verification for board-level fit.

Q: What is the difference between these two parts?

A: The primary differences are manufacturer (Ohmite vs. Vishay Dale), series designation (Acrasil® 80 vs. RS), physical dimensions, and moisture resistance feature. The RS01A20R00FS70 includes moisture-resistant construction and specifies an operating temperature range (-65°C to 250°C), while the 81F20R does not provide explicit temperature limits.

Q: Are there any compliance or certification differences?

A: Both parts are RoHS non-compliant and REACH Unaffected or REACH Affected respectively. Both carry ECCN classification EAR99. Verify compliance requirements for your specific application and regulatory jurisdiction before selection.

Q: Will the smaller size of RS01A20R00FS70 affect circuit performance?

A: No. Physical size does not affect electrical performance. The smaller diameter may require PCB layout adjustment for component placement and lead routing, but electrical characteristics remain identical.

Q: Which part should I choose for new designs?

A: Both parts are in active production. Selection should be based on supply chain availability, cost, and application-specific requirements such as moisture exposure or thermal environment. Verify operating temperature requirements against the specified range for RS01A20R00FS70 (-65°C to 250°C).