Specification Sheet: Model 110B-4991-FBW Precision Power Wirewound Resistor

Basic Information

• Product Series: 100 Series (Silicone Coated Precision Power Wirewound Resistors)
• Manufacturer: RCD Components Inc.
• RCD Type: 110B (corresponds to MIL Type RW81, as per 110 series specification)
• Resistance Value: 499Ω (derived from "4991" in P/N: 3 significant digits "499" + multiplier "1" = 499×1Ω = 499Ω; follows 1% & tighter tolerance coding rule: R10=0.1Ω, 1R0=1Ω)
• Tolerance: Implied as standard (not explicitly marked; 100 Series offers ±0.005% to ±10%, default aligns with general precision wirewound specs)
• Termination: W (RoHS compliant, standard for 100 Series)
• Packaging: B (Bulk packaging; T=Tape & Reel available for 102-176 types but not specified here)
• Special Option: F (Flameproof Coating, meets UL94V-0 standard)
• Compliance: RoHS Certified
• Stock Status: In Stock (consistent with 100 Series general stock availability)
• Delivery Program: Eligible for exclusive SWIFT'M delivery (standard for 100 Series)

Electrical Specifications

Power Ratings (Derating Required When Ambient Temperature >25°C)

• Standard Power (Char.U): 0.8W (max power for ±0.5% typical operational life stability, 275°C hotspot)
• Standard Power (Char.V): 1.0W (max power for ±3% stability, 350°C hotspot)
• Increased Power (Opt.B - Char.U): 1.5W (enhanced power option, applies to 110B type)
• Increased Power (Opt.B - Char.V): 2.0W (enhanced power option, applies to 110B type)

Resistance & Voltage

• Resistance Range Confirmation: 0.01Ω - 8KΩ (matches 110 series specification, 499Ω falls within this range)
• Maximum Voltage Rating: 40V (standard for 110 series; not to exceed wattage or current limits)
• Maximum Current: 15A (calculated via lead diameter: 110 series uses 0.024" lead diameter (Opt.22) as optional, corresponding to 15A max current; 0.020" lead (standard) = 11A, but 0.024" is typical for 110B)

TCR (Temperature Coefficient of Resistance)

• Standard TCR: 50ppm/°C (applies to 1-9.9Ω range, but 499Ω ≥10Ω; corrected to 20ppm/°C (standard for ≥10Ω in 100 Series))
• Optional TCR: 5ppm/°C, 10ppm/°C (available upon request for higher precision)

Pulse Capability

• Inherent Performance: Excellent pulse resistance due to all-welded wirewound construction (standard for 100 Series)
• Enhancement Option: 50%+ pulse capability boost via Opt.P (up to 500 joules), but not included in "FBW" (Opt.F only); pulse performance depends on pulse duration, repetition rate, and resistance value (consult factory for specific 499Ω/110B parameters)

Inductance (Standard, No Opt.X for Low Inductance)

• Typical Inductance: 1-50μH (small size of 110 series; higher than Opt.X levels)
• Low Inductance Alternative: Opt.X (not selected here) offers max series inductance at 0.5MHz: 0.2μH (≤50Ω) or 0.37μH (>50Ω, 499Ω falls here) for 102X-140X types; Opt.75 (50% of Opt.X) or Opt.76 (33% of Opt.X) for ultra-low inductance (not applied here)

Dielectric Strength

• Rating: 300V (applies to 102-156 types, including 110B; 500V available via Opt.23, not selected here)
• Overload (5 Seconds): 10× rated power (applies to 102-156 types, including 110B; 102-130 types = 5× rated power, 160-190 = 10×)

Physical Dimensions (inches [mm])

Performance Characteristics

Construction & Material

• Core: Thermally conductive ceramic (enables superior heat dissipation, standard for 100 Series)
• Winding: Premium grade resistance wire (welded construction for superior stability, standard for 100 Series)
• Coating:
• Leads: Tin (or SnPb) coated copper/copperweld (ensures solderability and shelf life)
• Marking: Minimum marking of resistance value (499Ω) and tolerance; custom marking available upon request

Ordering & Contact Information

• Full Part Number: 110B-4991-FBW
• Available Options (Not Selected Here):