D4D12 Solid State Relay: High-Performance MOSFET DC Output Relay for Industrial Automation

27 de enero de 2026

Historical parts record: Photos and notes below belong to this record. Confirm the offered unit’s full model, condition and available test evidence before ordering.

The Crydom D4D12 is a panel-mount solid-state relay that switches DC with DC — a 3.5–32 V DC input drives a 400 V DC, 12 A MOSFET output. Six units arrived new in the Crydom window boxes on 2026-01-26, all assembled in Mexico, date code 1846, with the clear terminal guard still fitted. For DC load switching (heaters on DC buses, DC solenoids, battery-cut duties) this is the panel-mount answer; it is not an AC-output SSR.

What the face says

Item	Value on body
Model	D4D12
Brand	Crydom (Sensata) — SOLID-STATE RELAY
Output	400 V DC, 12 A — terminals 1 (−) and +2
Input	3.5–32 V DC — terminals 4 (−) and +3
Date code	1846
Certifications	cULus, CE (UL file 10104 marking)
Origin	ASSEMBLED IN MEXICO

Crydom D4D12 with terminal guard — One relay with its clear guard on: the four screw terminals protected, the D4D12 face and UL marks visible, aluminum baseplate below.

D4D12 face close-up — Face-on: 1 — 400V⎓ OUTPUT 12A — +2 on the load side, 4 — INPUT 3.5-32V⎓ — +3 on the control side, cULus and the file-number triangle, ASSEMBLED IN MEXICO, D4D12.

The six units

Six D4D12 face up — All six, faces up — identical markings and date codes across the batch.

D4D12 baseplates close — Two baseplates close up — brushed aluminum, fixing hole and slot.

Six D4D12 baseplates — Baseplates up: the thermal pad surface for mounting to a heatsink, one fixing hole at top, slot at bottom.

D4D12 side view — Side view of one unit — guard, body and baseplate stack.

D4D12 sides CE marks — The sides carry CE, the 1846 date code and ASSEMBLED IN MEXICO on every unit.

D4D12 stacked sides — Stacked for the side view — guard clips and terminals in line.

Video: the six relays panned on the bench — faces, sides and baseplates in turn.

Packaging

D4D12 Crydom boxes — All six in the Crydom window cartons, faces visible through the film.

D4D12 single unit — A single relay in three-quarter view: guard, black body, aluminum base.

Fitting notes

Mount to a heatsink with thermal compound; at 12 A a MOSFET output still dissipates real watts and the baseplate is the only path out. The wide 3.5–32 V input takes PLC transistor outputs directly. Remember polarity on both sides — this is a DC-DC device, no zero-cross concept applies, and the load side does not tolerate reverse connection. The clear guard stays on in the panel; it is designed for live-terminals protection, not only for shipping.