The part number **39N-R** typically refers to a **Metal Oxide Varistor (MOV)**, a passive electronic component used for surge protection and voltage spike suppression. Below is a detailed breakdown of its specifications, function, and characteristics. --- ### 1. General Specifications While "39N" can appear in different manufacturer catalogs (like Littelfuse, TDK, or Panasonic), the nomenclature usually breaks down as follows: | Feature | Description | | :--- | :--- | | **Component Type** | Metal Oxide Varistor (MOV) | | **Nominal Varistor Voltage** | 39 Volts (The voltage at which the device begins to conduct) | | **Tolerance** | ±10% (Indicated by the "K" or sometimes "N" depending on the brand) | | **Suffix "-R"** | Typically indicates **RoHS Compliant** (Lead-free) | | **Form Factor** | Radial Leaded (Disc shape) | --- ### 2. How it Works A Varistor is a voltage-dependent resistor with a non-linear resistance characteristic. * **Under Normal Conditions:** The device has a very high resistance (acting as an open circuit) and does not interfere with the circuit operation. * **During a Voltage Spike:** When the voltage exceeds its threshold (39V), the resistance drops sharply. This allows the varistor to shunt the excess current to the ground, protecting sensitive downstream components. --- ### 3. Technical Parameters When selecting or replacing a 39N-R part, these electrical values are critical: | Parameter | Typical Value Range | | :--- | :--- | | **Working Voltage (AC)** | ~25V RMS | | **Working Voltage (DC)** | ~31V DC | | **Clamping Voltage** | ~77V (at specific peak current) | | **Peak Surge Current** | 100A to 1000A (depending on disc diameter) | | **Energy Absorption** | Measured in Joules (J) | --- ### 4. Common Applications * **Low Voltage Protection:** Used in automotive electronics and battery-powered devices. * **Communication Lines:** Protection for data ports and sensors. * **Power Supplies:** Acts as the first line of defense against line surges in DC power rails. --- ### 5. Identification Code Breakdown If you see this printed on a component: ```text 390N (or 39N) - 39: The base number - 0: The multiplier (10^0 = 1) -> 39 Volts - N: Tolerance code (±10%) - R: RoHS compliance ``` ---