Leading Power Semiconductor Manufacturer

Power Rectifier Diode Д171 Series (D171 Series)

The LJ-D171-400 (Д171-400) and LJ-D171-500 (Д171-500) Rectifier Stud Diodes are versatile power diodes designed to convert both DC and AC currents, accommodating loads of up to 500A and frequencies up to 500Hz in circuits with voltages ranging from 400V to 1800V (voltage class from 4 to 18). Enclosed in an SD7 package with a standard mounting thread of М24х1.5 (or upon request, UNF thread 3/4″-16UNF-2A), these diodes weigh 465 g and are supplied in a stud design.

The polarity of the diode is indicated by a symbol on the case: the threaded base serves as the Anode for forward polarity, while the flexible power lead acts as the Cathode. Conversely, for reverse polarity, the threaded base becomes the Cathode, and the flexible power lead becomes the Anode. Notably, forward polarity is not specified in the part numbering, while reverse polarity is marked with an “X” in the part numbering.

These power diodes can serve as alternative products, replacements, analogs, or equivalents for other diodes rated between 450A and 500A, all within a stud mount package. Air and water heat sinks are utilized for cooling purposes, ensuring efficient dissipation of heat. Proper thermal and electrical contact with the heat sink is maintained by adhering to a specific tightening torque (Md) during assembly, often complemented by the use of heat-conducting paste.

Featuring a hermetic ceramic housing that isolates the functional part and semiconductor element from mechanical impacts and environmental factors, these stud screw-fit diodes with flexible power leads are suitable for use on moving parts. Specifications, parameters, datasheets PDFs, sample technical passports, dimensions, outline drawings, case diagrams, and recommended heat sinks are available below.

Our company offers a 2-year quality guarantee for these power diodes, with options for additional documentation such as technical passports and certificates of conformity upon request. Diode ratings span a range of voltage classes, including D171-500-4 (500A 400V) through D171-500-18 (500A 1800V). The final price for phase control stud diodes depends on various factors such as voltage class, quantity, delivery terms, manufacturer, country of origin, and payment method.

Diode Normal/Reverse Polarity

LJД 17125018 UHL2 

  • LJ-MD 
  • Д Diode
  • 171 Series 
  • 400  Maximum permissible on-state current in amperes
  • 18 Class designation based on repetitive reverse voltage in hundreds of volts
  • UHL2 Class designation based on repetitive reverse voltage in hundreds of volts

For Symbols explanation CLICK HERE.

LJ-D171-400400 A300-1800 V625 A14.0 kA980 kA2·s1.4 V1256 A0.90 V0.56 mΩ50 mA190 ºC0.085 ºC/W30±5 N·m465 g
LJ-D171-500500 A400-1800 V785 A16.0 kA1200 kA2·s1.4 V1570 A0.90 V0.38 mΩ40 mA190 ºC0.085 ºC/W30±5 N·m465 g

For Any Help Or Datasheet

Looking to revolutionize your power control solutions? Look no further. At LJ-MD, we specialize in delivering cutting-edge diode and thyristor technologies that meet the highest industry standards. With a strong focus on innovation, reliability, and performance, our products are designed to excel in a wide range of power applications.


From high surge current capability to precise power control, our diodes and thyristors offer exceptional features that cater to your specific needs. Whether you require efficient rectification, fast switching, or precise phase control, our products deliver reliable and precise results.


At LJ-MD, we understand that every project is unique. That’s why we provide personalized support and guidance to ensure you find the perfect solution for your requirements. Our team of experts is always ready to assist you in selecting the right product and providing technical assistance.


Don’t miss out on the opportunity to optimize your power control systems. Contact us today to discuss your project requirements, and let us help you find the ideal diode or thyristor solution to drive your success.

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