DIY Club

DIY USB mobile charger 

🔌 DIY Variable Power Supply (5V to 18V) Using Transformer A variable power supply is essential for any electronics hobbyist. In this project, we’ll build a 5V–18V adjustable power supply using a step-down transformer , diodes , and a voltage regulator . 🔧 Components Required Component Specs / Notes Step-down Transformer 220V to 18V (center tap optional) Diodes (1N5408 x 4) For bridge rectifier (3A) Electrolytic Capacitor 1000µF – 2200µF / 35V LM317 Regulator IC Adjustable output Potentiometer 5k or 10k to adjust voltage Heat Sink For LM317 Resistors 220Ω & 2.2kΩ (for LM317 config) Output Terminals Banana jack or screw terminals Enclosure For safety and neatness ⚙️ How It Works Transformer steps down 220V AC to 18V AC. Bridge rectifier converts AC to DC. Capacitor smooths the DC voltage. LM317 regulates and lets you vary voltage from ~1.25V to 18V using a potentiometer . 🖼️ Basic Circuit Diagram (Text View) csharp Copy Edit [ 220V AC ] │ ▼ [ Step...