Signal relay offers space and power savings

The fifth generation of the HFD signal relays from Hongfa has a small board footprint, and features low coil holding power, providing advantages in industrial, medical and telecoms applications.

Hongfa has introduced the fifth generation of its HFD signal relays, providing space savings in applications that require isolated control of signal transmission.


At 9.0 mm x 4.8 mm x 4.9 mm, the HFD5 relays are 40% smaller by volume than the fourth-generation HFD relays, and occupy a board area which is 34% smaller.


The new HFD5 product also offers improved energy efficiency: coil holding power is just 50 mW, more than 64% lower than the fourth-generation relay. The improved efficiency saves power and helps to limit the temperature rise inside the relay, resulting in higher reliability and longer lifetime. The HFD5 is also notable for its quiet operation: audible noise when switching is a maximum of 30 dB.


Hongfa supplies relays in the HFD5 range that are compliant with the IEC 60079 or IEC 60335-1 standards. The range is available in single-side stable and latching type options, and with coil voltage options ranging from 1.5 V to 12 V.


  • Directly driven by microprocessor or microcontroller
  • 10 mA maximum operating current for 5 V coil
  • 2 A maximum switching current
  • 250 V ac/220 V dc maximum switching voltage
  • 100 mΩ maximum contact resistance
  • 2 ms maximum switching time
  • 750 V ac dielectric strength between open contacts
  • Bifurcated contacts
  • DIP and surface-mount package options


  • 5G mobile networking
  • Test equipment
  • Medical equipment
  • Video surveillance systems
  • Smart home devices
  • Automotive systems

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