Based on the model number provided, the **4-HT-2-R** refers to a specific type of **Precision High-Voltage Resistor** (typically manufactured by companies like Ohmite or specialized high-voltage component firms). These parts are designed for high-stability applications where voltage stress is a primary concern. --- ### 1. Key Electronic Specifications The "4-HT" series usually indicates a thick-film construction designed for high-resistance and high-voltage tolerances. | Parameter | Typical Value / Description | | :--- | :--- | | **Component Type** | Radial-leaded High Voltage Resistor | | **Resistance Range** | Often ranges from 100MΩ to several GΩ | | **Power Rating** | Typically 0.5W to 2W (depending on mounting) | | **Max Operating Voltage** | Can handle up to 5kV - 10kV DC | | **Tolerance** | Usually ±1% or ±5% | | **Temperature Coefficient** | Low TCR (e.g., 50ppm/°C to 100ppm/°C) | --- ### 2. Physical Construction The electronic properties of the 4-HT-2-R are derived from its specialized physical build: * **Substrate:** Alumina (Al2O3) ceramic core for excellent heat dissipation and electrical insulation. * **Resistive Element:** Thick film metal oxide or ruthenium oxide, printed in a serpentine pattern to minimize inductance and maximize the voltage path. * **Coating:** Encapsulated in a high-dielectric silicone or epoxy resin to prevent arcing and protect against humidity. * **Terminals:** Radial leads (the "-R" often denotes radial orientation) for vertical PCB mounting. --- ### 3. Application Use-Cases In an electronic circuit, the 4-HT-2-R is used where standard resistors would fail due to dielectric breakdown. * **Voltage Dividers:** Used in high-voltage power supplies to scale down kilovolt signals for monitoring. * **Medical Equipment:** Found in X-ray machines and MRI scanners. * **Scientific Instrumentation:** Used in mass spectrometers and electron microscopes. * **Bleeder Resistors:** Safely discharging high-voltage capacitors in power systems after shutdown. --- ### 4. Handling and Design Considerations 1. **Creepage and Clearance:** Because this part handles high voltage, PCB designers must ensure sufficient distance between the leads and other conductive traces to prevent surface tracking. 2. **Cleanliness:** Fingerprints (oils) on the body of the resistor can create a conductive path, leading to arcing at high voltages. They should be cleaned with isopropyl alcohol. 3. **Derating:** At high ambient temperatures, the power rating must be derated according to the manufacturer's thermal curve.