| Component | Value | Purpose | |-----------|---------|-------------------------------------------------------------------------| | C1 | 2200µF | Bulk input smoothing; reduces ripple from rectified AC. | | C2 | 100µF | Output filtering; improves transient response. | | C3 | 0.1µF | High-frequency decoupling; suppresses oscillations. | | D1-D4 | 1N4007 | Bridge rectifier (if AC input is used). | | LAC781P | - | +12V fixed regulator with internal current limiting and thermal shutdown. |
Detection pin, typically between 2.4V and 3.1V . lac781p schematic top
The always starts from the left. For the LAC781P, the input voltage must be at least 14.5V to maintain regulation (dropout voltage ~2V), but not exceed 35V (absolute maximum). A common input range is 15V–25V DC. lac781p schematic top