The **LU-5-R** is a specific model of a **Low-Profile Power Relay**, typically manufactured by brands like **IDEK** or **Fujitsu (Takamisawa)**. It is widely used in electronic circuits for signal switching and power control due to its compact size and reliability. --- ### 1. Technical Specifications The part number "LU-5-R" can be broken down to understand its core electronic characteristics: | Parameter | Specification | | :--- | :--- | | **Relay Type** | Electromechanical (Low Profile) | | **Coil Voltage** | 5V DC | | **Contact Arrangement** | 2 Form C (DPDT - Double Pole Double Throw) | | **Switching Capacity** | Typically 1A at 30VDC / 0.5A at 125VAC | | **Mounting Type** | Through-hole PCB (Printed Circuit Board) | | **Terminal Material** | Gold overlay silver alloy (for high reliability) | --- ### 2. Internal Components & Construction The LU-5-R consists of several critical electronic and mechanical parts: 1. **Electromagnetic Coil:** A winding of copper wire that creates a magnetic field when 5V is applied. The "R" in the suffix often denotes high sensitivity or specific resistance ratings. 2. **Armature:** A moving component that is pulled by the magnetic field to open or close the contacts. 3. **Contacts (DPDT):** It features two sets of change-over contacts. This allows it to control two separate circuits simultaneously. 4. **Return Spring:** Ensures the contacts return to their "Normally Closed" (NC) position once power is removed from the coil. 5. **Sealed Enclosure:** Usually plastic PBT, designed to protect the internal components from dust and soldering flux. --- ### 3. Pinout and Circuit Symbol While specific footprints vary by manufacturer, the standard 2 Form C (DPDT) layout follows this logic: ```text +-----------------+ | (1) (2) (3) | <-- Coil and Common pins | | | (4) (5) (6) | <-- NO/NC Contacts +-----------------+ ``` --- ### 4. Applications Because of its 5V coil and small footprint, the LU-5-R is commonly found in: * **Telecommunications:** Signal routing and switching. * **Consumer Electronics:** Power management in battery-operated devices. * **Industrial Control:** Interfacing between low-power microcontrollers (like Arduino/ESP32) and higher voltage peripherals. * **Medical Equipment:** Isolated signal switching.