The **ET1-R** is a specific model of an **automotive power relay** manufactured by NEC (now part of Tokin/KEMET). It is widely used in automotive electronics for its ultra-compact size and high switching capacity. --- ## 1. Technical Specifications The ET1-R is designed to handle high current loads while maintaining a small footprint on a PCB (Printed Circuit Board). | Feature | Specification (Typical) | | :--- | :--- | | **Relay Type** | Electromagnetic Power Relay | | **Coil Voltage** | 12 VDC (Standard automotive) | | **Switching Current** | 25A (Continuous) / 30A (Max) | | **Contact Form** | 1 Form c (SPDT - Single Pole Double Throw) | | **Contact Material** | Silver Oxide Complex | | **Mounting Type** | Through-hole (PCB Mount) | | **Operating Temp** | -40°C to +85°C | --- ## 2. Internal Components & Construction The ET1-R consists of several key electronic and mechanical parts: 1. **Electromagnetic Coil:** A copper wire winding that generates a magnetic field when 12V is applied, pulling the armature. 2. **Armature:** The moving metal piece that responds to the magnetic field. 3. **Contacts:** * **NO (Normally Open):** Connects when the relay is energized. * **NC (Normally Closed):** Connects when the relay is at rest. * **COM (Common):** The moving terminal. 4. **Spring Mechanism:** Ensures the armature returns to the default position when power is removed. 5. **Sealed Housing:** Often plastic-sealed to protect internal components from dust and automotive fluids. --- ## 3. Common Applications Because of its reliability and 25A rating, the ET1-R is typically found in: * **Power Windows:** Controlling the motor direction. * **Central Locking Systems:** Actuating door locks. * **Sunroof Controllers:** Managing motor movement. * **Wiper Controls:** Switching between speed settings. --- ## 4. Circuit Diagram Representation In an electronic schematic, the ET1-R is represented by a coil symbol and a switch symbol: ```text [ Coil ] [ Switch ] Pin 1 ----( )---- Pin 2 (Activation) | Pin 3 (COM) ----/ ---- Pin 4 (NC) \__ Pin 5 (NO) ``` ---