The **FTR-K3JB012W** is a high-performance power relay manufactured by Fujitsu. It is specifically designed for high-current switching applications, often found in power supplies and industrial equipment. ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Series** | FTR-K3 | | **Contact Arrangement** | 1 Form A (SPST-NO) | | **Nominal Coil Voltage** | 12V DC | | **Contact Rating (Resistive)** | 20A @ 250V AC / 30V DC | | **Maximum Switching Power** | 5,000 VA / 600 W | | **Coil Power Consumption** | Approx. 780 mW | | **Dielectric Strength** | 5,000V AC (between coil and contacts) | | **Mounting Type** | Through Hole (PCB) | --- ### 2. Detailed Electronic Characteristics #### A. Coil Side (Input) * **Nominal Voltage:** 12V DC. This is the voltage required to energize the electromagnet and close the contacts. * **Must-Operate Voltage:** Typically 75% of nominal voltage (approx. 9.0V). * **Must-Release Voltage:** Typically 10% of nominal voltage (approx. 1.2V). #### B. Contact Side (Output) * **High Inrush Capability:** The K3 series is engineered to handle high inrush currents, making it suitable for capacitive or inductive loads. * **Contact Material:** Usually Silver Tin Oxide (AgSnO2), which provides excellent resistance to "welding" (arcing damage) during high-current switching. * **Insulation:** It features a high insulation distance (creepage/clearance) to ensure safety between the low-voltage control side and high-voltage power side. #### C. Physical Construction * **Sealing:** The "W" suffix often denotes a "Flux Proof" or "Washable" construction, meaning the relay is protected against soldering flux during the manufacturing process. * **Dimensions:** It features a compact "sugar cube" or slightly larger rectangular footprint designed for high-density PCB mounting. --- ### 3. Common Applications * **Uninterruptible Power Supplies (UPS):** Used for switching between battery and mains power. * **Solar Inverters:** Managing the output of AC power from DC sources. * **White Goods:** High-power appliances like washing machines, air conditioners, and heaters. * **Industrial Controls:** Switching motors or large solenoids.