I would like to present a power supply I made from the begging. I had imagine this case and exactly it appears here and I make my vision true!
It’s a power supply 0-30 volts and 0-5 amber constantly ,we can increase the current up to 10 amber adding fans to the output tranzistors 2n3055.
Here is the circuit, as you can see we can adjust the voltage and the current too.
it consist of lm723 as current and voltage regulator and some components , With TR2 we adjust the MAXIMUM voltage so that don’t break out 30 volts, P adjust the voltage and TR1 adjust the current
The transformer has two windings 18-0-18Vac
here you can download pcb file
I have made a heatshink for the output power transistor 2n3055
I found a rectangular box and I place two hinge to the upper case and another two to the front case so that I can be opened and place the pcbs
and now I place the heatshinks with transistors to the back of the case
I bought two analog meters, one for amber one for volts for about 5 euro each from ebay
here I’ve place a filter from a power supply from computer ,a switch and a fuse
here is the section I place with to potentiometer the right we can adjust the volts and the left we can adjust the amper
the frond face, I have open a square hole at the center because I want to place a digital amber meter to measure miliambere 0-2000 miliamber, I ‘ll explain afterwards
at this point I decide I don’t like the color of the box, so I paint it ,but the color became dark enough !! it looks like a very old radio!! Lol but it continuous to be a power supply
I found two knobs in my drawer too, but unfortunately its not the same
Now lets continue with the pcd
I have use two electrolytic capacitors 4700mF 71 volt each but not new as you can see and not 4x2200mF 40 volt suggested from the circuit because I think 40 volts is not enough
I place all the stuff inside and I made the connections, the transformer is 2×18 volts ac taken from an old television
I place a bridge rectifier KBPC bought from ebay 50A 1000V mounted at a heat sink
you can have a closer look at this point watching the video
Here is the digital Ampere meter ,you can find diagram here
because the ic that use the voltmeter ICL 7107 need symmetrical sypply +/-5 volt and I did’t want to use symmetrical supply I made this circuit with 555 (IC2) timer so that use +5 volt supply
I use an old charger from mobile phone to supply the amper meter , it is a switching stabilizes supply 5 volt ,it is very small and reliable, best solution
as you can see at the following video, ammeter has a good responsibility, but i don’t know why its not stable, its moving +/-0-3 mA .Maybe the problem is the oscillator for 7107 .P1 trimmer is better to be used a multiturn trimmer so that to adjust it, with more accuracy
Now, i should place a switch so that to change the w
indings of the transformer, 18 vots or 36 volts, i found the proper one
My vision has come true! Its finished
i found a cover for display
Look at this video, its a test with a lamp 6V 0.5A, there is very good accuracy compering it with a multimeter
here I ‘ve a small modification, I replace 4 power transistor 2n3055, with four 2n3772. Those are newer and more stable in high current devices
Hello, Can you please send me a clear PDF or Word of the Schematic Diagram and the Components layout. And last thing – is this power supply gives 0V or around 1.7V to 30 V?
Hi , i am sorry i don’t have this in pdf or another schematic , it was only on a paper that they gave me. Output is 0.8v- 29.1V
Hey, TR1-adjust is for current limiter adjust. Not TR2.
You are right, i edit it .