The **MP82** is a specific surface-mount (SMD) Power Resistor developed by **Caddock Electronics**. It belongs to the Kool-Pak® series and is designed for power-hungry applications where space is limited but high heat dissipation is required. --- ### 1. Key Technical Specifications The MP82 is housed in a **TO-220 style** power package, which allows it to be mounted directly to a heatsink. | Feature | Specification | | :--- | :--- | | **Power Rating** | Up to 20 Watts (at +25°C case temperature) | | **Resistance Range** | 0.050 Ω to 10.0 KΩ | | **Tolerance** | ±1% (Standard), also available in ±5% or ±10% | | **Package Type** | TO-220 Style (Molded Plastic Case) | | **Operating Temp** | -55°C to +150°C | | **Inductance** | Non-inductive design | --- ### 2. Physical Design and Internal Construction The MP82 is built using Caddock’s proprietary **Micronox® resistance film**. This film is fired onto a flat ceramic substrate, providing several advantages: * **Heat Dissipation:** The ceramic substrate is thermally bonded to the copper heat sink tab. * **Isolation:** The molded plastic case provides electrical insulation from the mounting hardware. * **Non-Inductive:** Because it is a film resistor rather than wirewound, it has negligible inductance, making it ideal for high-speed switching applications. --- ### 3. Usage Guidelines To achieve the full **20W power rating**, the component must be properly managed: 1. **Heatsinking:** The device must be mounted to a thermal radiator (heatsink). Without a heatsink, the power rating drops significantly (usually to around 2.25 Watts at 25°C ambient air). 2. **Thermal Compound:** A thermal interface material (TIM) or silicone grease should be applied between the resistor’s metal tab and the heatsink. 3. **Derating:** As the case temperature rises above 25°C, the allowable power must be linearly derated to zero at 150°C. --- ### 4. Common Applications Due to its compact size and high power density, the MP82 is frequently found in: * **Power Supplies:** Used as a current sensing or bleeder resistor. * **Motor Controls:** Handling surge currents in drive circuits. * **Snubber Circuits:** Absorbing energy spikes in high-frequency switching. * **Audio Equipment:** Used in output stages where low inductance is critical for signal purity.