The term **2JS2** typically refers to a specific series of **High-Voltage Rectifier Diodes** (specifically Silicon Stack Rectifiers). These are primarily used in high-voltage power supplies, cathode ray tube (CRT) monitors, and X-ray equipment. --- ## 1. Technical Overview A 2JS2 diode is designed to handle high peak inverse voltages (PIV) while maintaining a small physical footprint. Because a single silicon junction cannot withstand several thousand volts, these components are "stacks" of multiple diode junctions connected in series inside a single molded package. ### Key Specifications (Standard Estimates) | Parameter | Typical Value | | :--- | :--- | | **Type** | High-Voltage Silicon Rectifier | | **Repetitive Peak Reverse Voltage ($V_{RRM}$)** | 2kV to 5kV (model dependent) | | **Average Forward Current ($I_{F}$)** | 5mA to 20mA | | **Maximum Forward Voltage Drop ($V_{F}$)** | ~10V to 15V | | **Operating Temperature** | -40°C to +120°C | --- ## 2. Structural Composition The internal architecture of a 2JS2 part differs from standard signal diodes: * **Silicon Stack:** Multiple p-n junctions are stacked vertically. This is why the forward voltage drop ($V_F$) is much higher (e.g., 12V) compared to a standard diode (0.7V). * **Encapsulation:** Usually housed in a cylindrical or rectangular epoxy resin body to prevent "arcing" (electrical sparks jumping across the terminal). * **Lead Material:** Tin-plated copper or silver-clad wires for high conductivity and heat dissipation. --- ## 3. Common Applications Due to their high voltage ratings and low current capacity, they are found in specialized circuits: 1. **TV/Monitor Flyback Transformers:** Used to rectify the high-voltage pulses required to drive a CRT screen. 2. **Negative Ion Generators:** Found in air purifiers to create high-voltage static fields. 3. **Electrostatic Precipitators:** Used in industrial filters to remove dust from air. 4. **Laser Power Supplies:** Providing the starting voltage for CO2 or HeNe laser tubes. --- ## 4. Identification and Polarity * **Cathode Marking:** A band or a "K" symbol usually denotes the cathode (negative end). * **Testing:** You cannot test a 2JS2 diode with a standard Multimeter "Diode Test" mode. Because the internal stack requires ~10V to conduct, a 9V or 3V multimeter battery will not show a reading, making the diode appear "open" even if it is working perfectly.