The **WJM-1B3-R** is a specific electronic component, typically categorized as a **Reed Relay**. These devices are used to provide galvanic isolation between a control circuit and a load circuit by using an electromagnet to operate a reed switch. Below is a detailed breakdown of its specifications and electronic characteristics. --- ### 1. General Specifications The "WJM" series is often associated with high-reliability reed relays used in telecommunications, testing equipment, and security systems. | Parameter | Typical Value / Description | | :--- | :--- | | **Component Type** | Reed Relay | | **Contact Form** | 1 Form B (Normally Closed / NC) | | **Package Style** | Through-hole (PCB Mount) | | **Lead Finish** | RoHS Compliant (indicated by the 'R' suffix) | | **Mounting** | Dual In-line Package (DIP) or similar | --- ### 2. Internal Electronic Parts The WJM-1B3-R consists of three primary internal sub-components: #### A. The Reed Switch This is the heart of the part. It consists of two ferromagnetic blades (reeds) hermetically sealed in a glass envelope filled with inert gas. * **Contact Material:** Usually Rhodium or Ruthenium to ensure low contact resistance and long life. * **Action:** In a "1B" configuration, the contacts are held together by a permanent internal bias or physical tension until the coil is energized. #### B. The Electromagnetic Coil A fine copper wire wound around the glass reed switch. * **Function:** When voltage is applied, it generates a magnetic field. * **Interaction:** In this "Normally Closed" model, the magnetic field from the coil pulls the reeds *apart* to break the circuit. #### C. Protective Diode (Optional/Variant Dependent) Some variants include an internal flyback diode connected across the coil terminals to suppress voltage spikes when the coil is de-energized, protecting sensitive driving transistors. --- ### 3. Electrical Characteristics To safely integrate this part into a circuit, the following parameters are critical: | Feature | Description | | :--- | :--- | | **Coil Voltage** | Usually available in 5V, 12V, or 24V DC versions. | | **Switching Voltage** | Typically rated up to 100V - 200V DC. | | **Switching Current** | Usually rated between 0.25A and 0.5A. | | **Isolation Voltage** | High dielectric strength between coil and contacts (often >1000V). | | **Response Time** | Extremely fast (typically <1ms) compared to mechanical relays. | --- ### 4. Typical Applications * **Security Systems:** Tamper-proof sensors and NC alarm loops. * **Test & Measurement:** High-speed signal routing where low capacitance is required. * **Telecommunications:** Line switching and isolation. ---