The **MP220B-R100-F** is a high-precision, high-stability **Metal Foil Power Resistor** manufactured by PCN (Precision Resistor Co.) or similar specialty resistor manufacturers. It is designed for applications requiring high wattage in a compact TO-220 style package. ### 1. Key Technical Specifications | Parameter | Value / Description | | :--- | :--- | | **Model Series** | MP220B | | **Resistance Value** | 0.100 $\Omega$ (R100) | | **Tolerance** | $\pm$ 1.0% (F) | | **Power Rating (with Heatsink)** | 20 Watts | | **Power Rating (Free Air)** | 2.25 Watts | | **Package Type** | TO-220 (Molded) | | **Temperature Coefficient** | Low PPM (typically $\pm$50 to $\pm$100 ppm/°C) | --- ### 2. Physical Design & Internal Construction The "B" designation in the part number often refers to the internal lead configuration or specific material bonding. * **Metal Foil Technology:** Unlike standard thick-film resistors, these use a metal foil element bonded to a ceramic substrate. This provides superior thermal stability and lower noise. * **TO-220 Housing:** The component looks identical to a transistor or voltage regulator. It features a metal tab with a mounting hole, which is essential for attaching a heatsink to dissipate the heat generated by the 20W rating. * **Non-Inductive:** Because of the flat foil construction, these resistors have very low inductance, making them suitable for high-frequency applications. --- ### 3. Part Number Breakdown Understanding the alphanumeric code helps in identifying replacements or variations: | Segment | Meaning | | :--- | :--- | | **MP220** | Series: Power Film Resistor in TO-220 package | | **B** | Sub-series/Lead style (usually refers to lead spacing or finish) | | **R100** | Resistance: 0.100 Ohms (The 'R' acts as the decimal point) | | **F** | Tolerance: $\pm$ 1.0% | --- ### 4. Common Applications Due to its low resistance (0.1 $\Omega$) and high power capability, the MP220B-R100-F is typically used in: 1. **Current Sensing:** Measuring current in power supplies by monitoring the voltage drop across the resistor ($V = I \times R$). 2. **Feedback Loops:** Used in motor control circuits and battery charging systems. 3. **Dummy Loads:** Providing a small, stable load for circuit testing. 4. **Pulse Handling:** Snubber circuits in switching power supplies where high-energy pulses occur. --- ### 5. Critical Installation Note **Thermal Management:** If you draw more than 2 watts through this resistor, it **must** be mounted to a heatsink using thermal grease. Without a heatsink, the component will overheat and fail rapidly, as the "Free Air" rating is only about 10% of its maximum capacity.