The **FTR-K3JB012W-HC** is a high-power, PCB-mount electromechanical relay manufactured by **Fujitsu**. It is specifically designed for high-current loads and is commonly found in home appliances and industrial controllers. --- ### 1. Technical Specifications The following table summarizes the primary electrical and physical characteristics of the component: | Feature | Specification | |:---|:---| | **Contact Form** | 1 Form A (SPST-NO) | | **Coil Voltage** | 12 VDC | | **Rated Contact Current** | 20A (Steady State) | | **Max. Switching Voltage** | 250 VAC | | **Power Consumption** | Approx. 780 mW | | **Contact Material** | Silver Tin Oxide (AgSnO2) | | **Dielectric Strength** | 5,000 VAC (between coil and contacts) | | **Insulation Distance** | 8.5 mm (Clearance/Creepage) | --- ### 2. Key Internal Components - **The Coil (12V):** When 12V DC is applied, the coil creates a magnetic field. This pulls the armature toward the core. - **The Armature:** A moving lever that transfers mechanical force from the magnetic field to the electrical contacts. - **AgSnO2 Contacts:** The "HC" in the part number often signifies **High Current**. Silver Tin Oxide is used because it resists "welding" (sticking together) during high inrush currents, such as when starting a motor. - **Reinforced Insulation:** The physical design provides high isolation between the low-voltage control side (coil) and the high-voltage load side (contacts). --- ### 3. Pinout and Physical Construction The device is housed in a "Flux Proof" or "Sealed" plastic casing. 1. **Coil Terminals:** Two pins used to trigger the relay. 2. **Load Terminals:** Two heavy-duty pins for the "Normally Open" circuit. 3. **Mounting:** Through-hole technology (THT) for secure soldering onto a Printed Circuit Board (PCB). --- ### 4. Typical Applications Because of its 20A rating and high insulation, this part is ideal for: * **HVAC Systems:** Controlling compressors or heaters. * **Smart Plugs:** Switching heavy domestic loads. * **EV Chargers:** Level 1 or basic charging control circuits. * **Washing Machines:** Managing motor or heating element power.