Make Your Own Power Supply !! Elecrom October 15, 2007; Updated On: December 8th, 2016 2 Power supply is foremost important thing for any electronic hobbyist. Making one variable voltage power supply at home is extremely simple. To make your own power supply, you need just a few components and one pretty nice transformer which can wholeheartedly supply enough current for your needs while staying cool !!. LIST OF COMPONENTS : 1)Transformer 0-18 Volt, 1 Amp [ alternative: 9-0-9, 1Amp] 1 2)LM317 – variable voltage regulator 1.5A (TO-220 package) 1 3)Diodes 1N5408 1N4007 4 2 3)Capacitors 2200µF(or more),50V(or more) 470µF,50V(or more) 10µF,50V(or more) 1 2 1 4)Resistor 220E, 1/4 W 1 5)Pot D25 Male 1 6)Grid PCB 3″ x 3″(approx) 7)Connecting wires – – CIRCUIT DIAGRAM : NOTES : Do not use transformer with output more than 0-18 V (or 9-0-9), because their no load voltage goes upto 22-28V depending upon manufacturer. If you use higher o/p voltage transformer (say 0-24) its no load voltage may reach to 35-40V, which will damage LM317, once LM317 gets damaged, it will short i/p to o/p and full voltage will get connected to your circuit under test, thereby ruining the circuit. C1 should be as large as possible to get very good power supply ripple rejection. C2 and R2 should be soldered as close as possible to LM317· Heat sink is recommended for LM317. Try to obtain transformers current rating which is at least 1.5 times your maximum requirement. If u drive transformer considerably long time at its maximum rating it will become quite hot. Use plastic tape to properly cover AC mains and transformer connection. Slight carelessness here would lead to a nasty shock.
