F4901 1.1a 24v Schematic Direct

This is the "smart" part of the schematic. Resistors R5 and R6 form a voltage divider. When the output exceeds 24V, the TL431 (U3) conducts more current. This current flows through the LED inside the PC817 optocoupler. The phototransistor side of PC817 pulls the FB (feedback) pin of the primary IC low. The IC responds by reducing the ON-time of Q1, lowering the output voltage. This creates a stable 24V ±2%.

This report outlines the technical specifications and application of the component within high-performance laptop motherboards (typically Wistron designs for brands like Lenovo, Acer, and Dell). 1. Component Identification The f4901 1.1a 24v schematic

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