The **VDR10D112K** is a specific model of a Metal Oxide Varistor (MOV). It is a passive electronic component used primarily for voltage surge protection in electronic circuits. --- ### 1. Part Number Breakdown The alphanumeric code provides specific technical details about the component: | Code Segment | Meaning | Description | | :--- | :--- | :--- | | **VDR** | Voltage Dependent Resistor | The generic category of the component (Varistor). | | **10** | Element Size | Refers to the disc diameter (10mm). | | **D** | Shape | Indicates a Disk-shaped component. | | **112** | Varistor Voltage | $11 \times 10^2 = 1100V$. This is the nominal voltage. | | **K** | Tolerance | Indicates a $\pm 10\%$ tolerance on the voltage rating. | --- ### 2. Key Technical Specifications Based on the standard 10D112K datasheet parameters: * **Varistor Voltage:** 1100V (Measured at 1mA DC). * **Maximum Allowable Voltage:** * **AC RMS:** ~680V * **DC:** ~895V * **Clamping Voltage:** Approximately 1815V (The maximum voltage the device will allow through during a surge). * **Withstanding Surge Current:** Typically 2500A (8/20μs pulse). * **Energy Absorption:** ~115 to 140 Joules. --- ### 3. Functional Characteristics The VDR functions as a **non-linear resistor**. Its resistance changes based on the applied voltage: 1. **High Resistance State:** Under normal operating conditions (below 1100V), the VDR has very high resistance, acting like an open circuit. 2. **Low Resistance State:** When a high-voltage spike (surge) occurs, the resistance drops instantly. 3. **Shunting Action:** By dropping its resistance, it "shunts" (diverts) the excess current to the ground or neutral, protecting sensitive downstream components from overvoltage. --- ### 4. Applications The VDR10D112K is typically used in high-voltage environments due to its 1100V rating: * **Industrial Electronics:** Power supplies and motor controllers. * **Lighting:** LED drivers and ballast protection. * **Telecommunications:** Protection for power lines. * **Consumer Appliances:** Protection against lightning strikes and power grid switching transients. --- ### 5. Circuit Symbol and Installation The varistor is typically placed **in parallel** with the load it is intended to protect. ```mermaid graph LR Line --- VDR VDR --- Neutral Line --- Load Neutral --- Load ```