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.