Simple 5 Ampere Power Supply

Power supply is a must used circuits. Most of electronic devices which require DC voltage usually need a power supply. Some of them just need original power supply or battery, but some of circuits like Radio transmitter or amplifier needs high current output power supply.

This project is a simple and easy made 5 ampere power supply. To build this circuit, just follow the instruction below:

This is a fixed, but variable, power supply developed for ease of design and building. The power supply is capable of supplying almost 5A with the right components. The right components are a stable 5A transformer, bridge rectifier and a heatsink that can dissipate the excess power developed in this type of power supply. I have limited the current to just over 3A with a fuse, as I have found that, this in practice is about the maximum current that can be drawn before the system becomes too hot.

The circuit diagram is shown in Fig. 1, and as you can see, it really is a simple circuit.


Figure 2 show the diagramatic (pin side/inside view) view of IC1, and most of the other components, mounted on a large heatsink. It is important that the LM338K integrated circuit be insulated from the heatsink. No printed circuit board is needed as most of the components are mounted on the heatsink

The integrated circuit IC1, has all the active power supply control circuitry on board.
Output can be designed to be almost any value between 1.2V and the regulator’s limit of 35V. For the higher voltages, some changes would have to be made to the transformer, diode and filter capacitor circuitry.

Here is a small table to help you achieve the output voltage you need.

Vout New R1

1.5V 68 Ohm
3V 390 Ohm
4.5V 680 Ohm
6V 1K
7.2V 1.2K
9V 1.8K
12V 2.2K
15V 3K
20V 3.9K
24V 5.1K
28V 6K

This table is not meant to be highly accurate, but just to give an indication of the required resistance to replace R1. At higher output voltages, you may need to modify the resistance slightly to get a more accurate voltage output. Give this project a try, you will enjoy building and using it.

PARTS LIST:

Resistors:
1 X 270 ohm R2
1 X 470 ohm R3
1 X 2.7k ohm R1

Capacitors:
Mylar 160V
1 X 220n C3
Electolytic 25V
1 X 1uF C2
1 X 15000uF C1

Semiconductors:
1 X LM338K IC1
1 X Bridge Rectifier 5A

Miscellaneous:
1 X 100VA 15V transformer
1 X 3.15A fuse and fuse holder
1 X Red Led
Suitable Heatsink
Cabinet.

Info on some of the components used:




Enjoy building this simple but very effective 5 volt Power Supply.