The **WJM-1FB-R** is a specific model of a **Miniature Intermediate Relay**, commonly used in industrial control systems and automation. Below is a detailed breakdown of its electronic parts, technical specifications, and internal architecture. --- ### 1. General Overview The WJM-1FB-R is an electromagnetic switching device. It allows a low-power signal to control a high-power circuit. The "-R" suffix often indicates a specific mounting style (such as PCB mount) or a specific environmental protection rating. ### 2. Core Electronic Components A relay of this type consists of four primary internal parts: | Component | Material/Type | Function | | :--- | :--- | :--- | | **Electromagnetic Coil** | Copper Wire (Enameled) | Converts electrical energy into a magnetic field when energized. | | **Armature** | Ferromagnetic Metal | A moving lever that is pulled toward the coil by the magnetic field. | | **Contacts** | Silver Alloy (AgNi or AgSnO2) | The "switch" points that open or close the secondary circuit. | | **Spring Mechanism** | High-tensile Steel | Returns the armature to its original position when power is removed. | --- ### 3. Technical Specifications The performance of the WJM-1FB-R is defined by its electrical ratings: #### A. Input (Coil) Side * **Nominal Voltage:** Usually available in DC variants (5V, 12V, or 24V). * **Pick-up Voltage:** The minimum voltage required to engage the relay (typically 75% of nominal). * **Drop-out Voltage:** The voltage level where the relay releases (typically 10% of nominal). #### B. Output (Contact) Side * **Contact Form:** Typically 1C (SPDT - Single Pole Double Throw). * **Max Switching Current:** Generally rated around **10A to 12A**. * **Max Switching Voltage:** 250VAC / 30VDC. * **Contact Resistance:** $\le 100m\Omega$. --- ### 4. Terminal Pin Layout The WJM-1FB-R usually follows a standard 5-pin configuration for PCB mounting: 1. **Pin 1 & 2 (Coil):** Connection points for the control signal. 2. **Pin 3 (Common - COM):** The input terminal for the load power. 3. **Pin 4 (Normally Closed - NC):** Connected to COM when the coil is **OFF**. 4. **Pin 5 (Normally Open - NO):** Connected to COM when the coil is **ON**. --- ### 5. Application Circuit Example To use this part safely in a digital circuit (like with an Arduino), a **Flyback Diode** must be used to protect against inductive spikes. ```cpp // Pseudocode for triggering the relay void setup() { pinMode(RELAY_PIN, OUTPUT); } void loop() { digitalWrite(RELAY_PIN, HIGH); // Coil energizes, NO closes delay(1000); digitalWrite(RELAY_PIN, LOW); // Coil de-energizes, NO opens delay(1000); } ``` ---