The **WJ-R** series (often associated with high-frequency coaxial switches or specialized communication relays, such as those from companies like **WJ Communications** or specific RF relay manufacturers) generally refers to a line of **Electromechanical Coaxial Switches** or **RF Relays**. Below is a breakdown of the electronic parts and functional components typically found in a WJ-R style device. --- ### 1. Key Internal Components | Component | Description | Material/Type | | :--- | :--- | :--- | | **Solenoid / Actuator** | The core electromagnetic coil that drives the mechanical switching action. | Copper winding with an iron core. | | **Contacts** | The electrical connection points that open or close the signal path. | Often Gold-plated Beryllium Copper for low resistance. | | **RF Connectors** | The physical interface for the input/output signals. | SMA, Type N, or TNC (depending on power requirements). | | **Return Springs** | Ensures the switch returns to a "failsafe" or default state when power is removed. | Stainless steel or specialized alloys. | | **Housing** | Provides EMI/RFI shielding and physical protection. | Aluminum or Nickel-plated steel. | --- ### 2. Functional Electronic Principles The WJ-R components operate based on the following electronic mechanisms: #### A. The Actuation System The device uses a **DC voltage** (typically 12V, 24V, or 28V) to energize a solenoid. When current flows through the coil: 1. It creates a magnetic field. 2. The magnetic field pulls an armature. 3. The armature moves the contact assembly from one position (e.g., Normally Closed) to another (e.g., Selected). #### B. Signal Integrity Parts Because these are used in RF (Radio Frequency) applications, the internal geometry is critical: * **Impedance Matching:** The internal paths are precision-machined to maintain a constant **50 Ohm** impedance. * **Isolation:** The distance between open contacts is calculated to prevent signal "leakage" (crosstalk) between ports. #### C. Indicator Circuits (Optional) Some WJ-R models include an auxiliary set of electronic contacts known as **Indicators**. These allow a remote control system (like a computer or PLC) to verify that the switch has physically moved to the desired position. --- ### 3. Common Technical Specifications When looking at the electronic datasheet for a WJ-R part, you will typically encounter these values: * **Frequency Range:** DC to 18 GHz (or higher depending on the specific sub-model). * **Insertion Loss:** Usually < 0.5 dB (measures how much signal power is lost). * **VSWR (Voltage Standing Wave Ratio):** Ideally < 1.5:1 (measures signal reflection). * **Switching Time:** Typically 15ms to 20ms. --- ### 4. Schematic Representation A basic SPDT (Single Pole Double Throw) WJ-R switch circuit looks like this: ```text [ Coil + ] ----( ( ( ) ) )---- [ Coil - ] | | (Magnetic Force) V [ Port 1 ] <---------[ Common ]----------> [ Port 2 ] (NC) (NO) ``` ---