What this connector is
The Amphenol FCI 79821-152HLF is the 52-circuit member of the BERGSTIK II board-to-board header series — a dual-row, 0.100 inch (2.54 mm) pitch unshrouded header with push-pull through-hole termination. All 52 positions are loaded with gold-plated square pin contacts rated 5A per circuit at 110V. The 0.100 inch (2.54 mm) insulation height sets the mated stack height for the board-to-board pair, while the 30.0 µin (0.76 µm) gold finish on the mating interface gives the contact durability headroom for the stated cycling duty.
What it does and where it goes
A board-to-board stacking header — the 0.100 inch (2.54 mm) pitch and 5A per-circuit rating make this suited for signal and low-level power distribution in industrial control cards and instrumentation front panels. The UL94 V-0 housing material satisfies the base flammability requirement for most industrial and commercial equipment enclosures.
Plating grade and what it means for mating cycles
The 30.0 µin (0.76 µm) gold finish on the mating contact is the meaningful spec — it defines the wear budget for the number of insertion and withdrawal cycles the pair can survive before the contact surface degrades past the resistance threshold. At 30 µin gold over nickel, the BERGSTIK II header falls into the upper tier of tin-gold finishes for this pitch class: it will handle substantially more reconnect cycles than a tin-only finish before the underlying nickel扩散 layer is exposed. For a header specified as a permanent board-to-board stack — where the pair is mated once at final assembly and not normally separated — the plating grade is comfort margin rather than a selection driver; it matters most when the application involves field service, fixture swapping, or module replacement cycles.