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 :
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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.
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C1 should be as large as possible to get very good power supply ripple rejection.
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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.
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Use plastic tape to properly cover AC mains and transformer connection. Slight carelessness here would lead to a nasty shock.
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Just go to the electronics shop from where you buy LM317 and ask him heat sink for that. Heat sink is nothing but a piece of metal which is having more surface area for quicker heat dissipation and is attached to the device so as to help heat dissipation. As load current increases, LM317 will get hotter, if you don’t fit heat sink to it, its temperature will go on increasing and IC’s will get shut off due to excessive heating. Whereas if you fit heat sink then Heat produced by the IC will get transferred to heat sink and then in-turn will be dissipated to air.
http://en.wikipedia.org/wiki/Heat_sink
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Hey….what do we use as heat sink……i’m a complete novice in these things….please suggest some good heat sinks and reference links related to heat sinks……you could actually put up your own designed power supply’s images.