News

TT Electronics launches UL-recognised fusible and high surge SMD resistors

New MELF format flameproof wirewound resistors offer surge protection and UL1412 failsafe fusing for line input protection in industrial and white goods applications

Woking, UK, 28th May 2025 - TT Electronics, a global provider of engineered electronics for performance critical applications, today announced:
 

• Two new and related product series; FMW fusible MELF wirewound resistors and HSMW high surge MELF wirewound resistors. Both are 0309 size products rated at 1W and offering UL1412 fusing at up to 240V. FMW is designed for optimised fast fusing performance whilst HSMW is built to deal with larger inrush or power line surges.

 

• Building on TT’s expertise in wirewound resistors engineered to meet demanding pulse and fuse requirements, this is the first true SMD offering with UL recognition.

 

• The compact footprint of 9 x 3.5mm saves PCB space compared to lead-formed SMD (Z-form) alternatives.

 

• Rapid line voltage fusing protects products against fire if a fault develops in the power supply input circuit.

 

• With a short-term overload rating up to 6.25W for 5s and high energy capacity up to 6.5J, these robust solutions are designed to withstand high inrush currents and lightning strike surges of up to 3.5kV.

 

• These new protection resistors give designers the opportunity to reduce product size and cost whilst maintaining high levels of safety and reliability.