Use an old Nokia charger to power 1W LED
Here is one useful trick I invented when looking around the transformers/power supplies I had. NOKIA ACP-7 Europe Standard Charger (Original) has a specification of 230 V, 50 Hz, 4.8 VA. Output 3.7 V, 355 mA. A normal 1W white LED is driven with 350 mA maximum continuous current and typically 3-3.8V voltage drop over →