Advanced welded spot of anti-surge wire wound resistor / More than 50 years of resistor manufacture experience

The wire wound resistors have been around for more than a half of century, they are usually existing in high power circuit design, but are not suitable for anti-surge applications. The reason is a reliability problem of solder joint between alloy wire and metal cap, when the wire wound resistors are produced, the joint of the welded spot and metal cap may have false welding on the welded spot. Hence, the welded spot will be easily broken when surge across it with huge energy. FIRSTOHM Advanced welded spot of anti-surge wire wound resistor Introduction. More than 50 years of resistor manufacture experience. FIRSTOHM is one of the few companies who is able to design thin-film resistors according to customer's requirements with high quality and reliability. We’re specialized in MELF resistors since 1969, ISO9001/14001 certificated manufacturer.

qrc@firstohm.com.tw

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The wire wound resistors with patents of weld spot.

Advanced welded spot of anti-surge wire wound resistor

The wire wound resistors have been around for more than a half of century, they are usually existing in high power circuit design, but are not suitable for anti-surge applications. The reason is a reliability problem of solder joint between alloy wire and metal cap, when the wire wound resistors are produced, the joint of the welded spot and metal cap may have false welding on the welded spot. Hence, the welded spot will be easily broken when surge across it with huge energy.


Implement

FIRSTOHM realize the reliability of the welded spot is a key factor to withstand surge. Therefore, after the wire wound welding, a layer of alloy is plated on the surface of the welded spot, and the reliability is improved. Below pictures show original welded spot and after implement:

Traditional wire-wound resistor
Original - Traditional wire-wound resistor – Welded spot is not reliable against surge

Improved anti-surge welded spot
FIRSTOHM - Improved anti-surge welded spot

SWAT/SWMT : Anti-Surge Wire Wound Fast-Fuse (MELF) Resistor

Feature
  • Worldwide patent pending.
  • Enhanced welded spot is reliable against surge.
  • Fast-acting fuse device for high power applications.
  • Advanced combined anti-surge & fast-fuse structure.
  • Flameproof multi-layer coating equivalent to UL 94 V-0.
  • Flameproof feature equivalent to overload test UL 1412.
  • Thermal fuse to protect against overheating in electronic products.
Reference Design
Illustration of Anti-Surge Wire Wound Fast-Fuse (MELF) Resistor in circuit
Structure
To emphasize position of thermal fuse and explain how to structure a wirewound resistor
Application
  • Power supply
  • Charger for mobile phone
  • LED Lighting
  • Motor star-up protection
  • Motor ignition
General Specification

The specifications of Anti-Surge Wire Wound Fast-Fuse (MELF) Resistor

High-End MELF SMD Resistors Manufacturer - FIRSTOHM

Located in Taiwan since 1969, First resistor & condenser Co. Ltd. is a MELF type resistor manufacturer. ISO9001/14001 certificated, award winning and patented design thin-film resistors, including anti-surge resistor, precision resistor, stability resistor, high voltage resistor, current sense resistor, automotive grade resistor, high power resistor, circuit protection resistor, fusible resistor and so forth.

FIRSTOHM's resistors are being widely used in industry applications, such as power supply, telecom, meter, medical, automotive and lighting. The strong R&D has allowed FIRSTOHM to develop new technology and obtain hundreds of patents, as well as develop specialty resistors, such as high voltage resistor, short circuit protection resistor, dual power resistor, high humidity resistor, etc.

FIRSTOHM has been offering customers high quality MELF resistors since 1969, both with advanced technology and 50 years of experience, FIRSTOHM ensures each customer's demands are met.