The **HVS-5D-R** is a specialized high-voltage reed relay, typically manufactured by companies like **Standex Electronics (OKI/Meder)**. It is designed for applications requiring high isolation voltages and reliable switching in a compact form factor. --- ## 1. Core Specifications The electronic performance of the HVS-5D-R is defined by its ability to handle high potential differences while maintaining low contact resistance. | Parameter | Specification (Typical) | | :--- | :--- | | **Contact Form** | 1 Form A (SPST-NO - Normally Open) | | **Coil Voltage** | 5 VDC | | **Max Switching Voltage** | Up to 1,000 VDC | | **Breakdown Voltage** | Up to 3,000 VDC (Dielectric Strength) | | **Max Switching Current** | 1.0 A | | **Max Carry Current** | 2.5 A | | **Contact Resistance** | < 150 mΩ | --- ## 2. Key Electronic Components & Design ### A. The Reed Switch The heart of the device is a hermetically sealed glass envelope containing two ferromagnetic blades (reeds). * **Atmosphere:** The tube is usually filled with high-pressure nitrogen or evacuated to a vacuum to prevent arcing during high-voltage switching. * **Plating:** The contacts are often plated with Rhodium or Tungsten to endure the thermal stress of high-voltage sparks. ### B. The Electromagnetic Coil The "5D" in the part number signifies a **5 Volt DC** nominal coil voltage. * **Power Consumption:** Designed for low power consumption, allowing it to be driven directly by logic gates or small transistors. * **Sensitivity:** The coil creates a magnetic field that pulls the reed blades together to close the circuit. ### C. Internal Protection * **Insulation Resistance:** The internal potting material and glass envelope provide insulation resistance typically exceeding $10^{10} \Omega$. * **Electrostatic Shielding:** Some variants include an internal shield to reduce noise interference between the high-voltage side and the low-voltage control side. --- ## 3. Applications Because of its high dielectric strength and small footprint, the HVS-5D-R is commonly used in: 1. **Automated Test Equipment (ATE):** For testing insulation and cable harnesses. 2. **Medical Electronics:** Specifically in defibrillators or imaging equipment where isolation is critical for patient safety. 3. **Solar/Renewable Energy:** Monitoring isolation resistance in photovoltaic strings. 4. **Battery Management Systems (BMS):** High-voltage stack monitoring. --- ## 4. Basic Wiring Diagram To drive this relay using a microcontroller (like an Arduino), a flyback diode is essential to protect the driving circuit from inductive spikes. ```cpp // Logic for driving the HVS-5D-R via a NPN transistor // Pin Layout: // [Coil +] -> 5V Supply // [Coil -] -> Collector of NPN Transistor // [Emitter] -> GND // [Base] -> Resistor to Microcontroller Pin ```