The **OR2-D-R/Q** refers to a specific configuration of a **Solid State Relay (SSR)**, typically manufactured by companies like **Okita** or specialized industrial component suppliers. This specific model is a Reed Relay designed for high reliability and isolation. --- ## 1. Technical Specifications Overview The part number breaks down into specific electrical characteristics. Below are the typical parameters for this series: | Parameter | Specification | | :--- | :--- | | **Contact Form** | 2 Form A (DPST-NO) | | **Coil Voltage** | 5V DC (Standard for 'D' series) | | **Max Switching Voltage** | 200V - 500V (depending on load type) | | **Max Switching Current** | 0.5A | | **Contact Resistance** | < 150 mΩ | | **Package Type** | DIP (Dual In-line Package) | --- ## 2. Key Electronic Components & Construction ### A. Reed Switch Mechanism The core of the OR2-D-R/Q consists of two ferromagnetic blades (reeds) hermetically sealed in a glass tube filled with inert gas. - **The "R" Suffix:** Usually denotes high reliability or enhanced rhodium-plated contacts to prevent sticking and ensure long life cycles (up to $10^8$ operations). ### B. Electromagnetic Coil Surrounding the reed switches is a copper wire coil. When current flows through the coil: 1. It creates a magnetic field. 2. The field magnetizes the reeds. 3. The reeds attract each other, closing the circuit. ### C. Protection Diode (The "Q" Suffix) The **"Q"** in the part number often signifies an **Integrated Internal Diode** connected in parallel with the coil. - **Function:** It acts as a flyback (snubber) diode. - **Benefit:** When the coil is de-energized, the magnetic field collapses, creating a high-voltage spike. The diode clamps this spike to protect the driving transistor or microcontroller from damage. --- ## 3. Circuit Application These parts are commonly used in automated testing equipment (ATE) and telecommunications due to their low power consumption and high speed. ### Sample Wiring Logic ```text [VCC 5V] ----+---- [Coil Pin 1] | [Diode] (Cathode) | [Control Signal] -- [Coil Pin 2] ``` --- ## 4. Advantages of this Model * **High Isolation:** Provides excellent galvanic isolation between the control and load circuits. * **Built-in Protection:** The "Q" variant eliminates the need for external protection components on the PCB. * **Dual Channel:** The "2" in the prefix indicates two independent switches controlled by a single coil, allowing for simultaneous switching of two lines.