It is the variable current power supply which give output of 12V 1A-5A
its a designed PCB
Input is by 12V 5A transformer
you can also increase the current rating of the power supply by using more no. of voltage regulater IC;
Step 1: Things You Need
1) one 10 ampere Bridge rectifier.
2) Two 4700uF 50V capacitor
3) four 0.1uf disc capacitor
4) four 7812 voltage regulater
7) heatsinks (four for voltage regulater and one for rectifier)
8) 5A 220V-12V transformer
Step 2: Connection Diagram
C1, C2 is the electrolytic capacitor(4700uF 50V) is in parallel with the DC output(12v) the other C3-C6 are also in parallel with the supply (along with the 4700uf) ,so the Dc supply is filtered.
connect 7812 regulater IC in parallel and then connect the input and the ground terminal of 7812 with the filtered Dc output.
I have designed the power supply on eagle.
you can also do it on zero PCB.
WARNING- dont test this circuit on breadboard as it will melt the holes as the current is too high.
output can be collected from JP4 (1 ampere)
when we short JP1 we get 2amperes at JP5
when we short JP2 (JP1 still short) we get 3 amperes at JP6
when we short JP3 we get 4amperes at the last no name jumper.
A COMMON GROUND IS GIVEN AT IC4
Use heat sinks on all the regulater IC's as well as the bridge rectifier to dissipate heat.
you can also use 7805 IC to get 5V output.
Step 3: Results
you can see the output 1 ,2 and 4.5 ampere after shorting the pinheaders.
you can also increase the output current rating of the power supply by using more no. of voltage regulater IC's in parallel and using a and using a transformer above 5A
for 24V output you can use 7824 voltage regulater in place of 7412