0-30 Vdc Stabilized Power Supply

[Kasamiko]

Ok after so much discussion and arguments. Can someone post the UPDATED and CORRECTED schematics for this project..
One that is "NEAR" perfect.. 8)

Rhonn

 

[kobus1]

Hello Kasamiko.
I don't know about 0-30V 0-3A power supply but see under electronic forums-->project design/ideas-->modify 0-30V supply
or something like that.On the last page is pretty much a summary of what audiophile thinks should be modified for a 5A supply.No-one knows yet if it works so no guarantees.I'm currently building the supply in my spare time and hope to have it done some time end of next week. Hope this helps.

 

[kobus1]

sorry meant audioguru!!

 

[audioguru2]

Kasamiko, and others,
My replies in this forum and the Parts List that follows will allow this project to meet its own specs and to operate reliably.

Parts List for 3A Variable Power Supply

*T1 = 30VAC, 4.3A, 130VA stepdown power transformer
*R1 = 2,2 KOhm 2W
R2 = 82 Ohm 1/4W
R3 = 220 Ohm 1/4W
R4 = 4,7 KOhm 1/4W
R5, R6, R13, R20, R21 = 10 KOhm 1/4W
*R7 = 0,47 Ohm 10W
R8, R11 = 27 KOhm 1/4W
R9, R19 = 2,2 KOhm 1/4W
R10 = 270 KOhm 1/4W
R12, R18 = 56 KOhm 1/4W
*R14 = 1,2 KOhm 1/4W
*R15 = 100 Ohm 1/4W
R16 = 1 KOhm 1/4W
R17 = 33 Ohm 1/4W
*R22 = 3,9 KOhm 1W
RV1 = 100K trimmer
P1, P2 = 10KOhm linear potentiometer
*C1 = 10,000uF/50V electrolytic
C2, C3 = 47uF/50V electrolytic
C4 = 100nF polyester
*C5 = 220nF polyester
C6 = 100pF ceramic
C7 = 10uF/50V electrolytic
C8 = 330pF ceramic
C9 = 100pF ceramic
*D1, D2, D3, D4 = 6-10A/50V diode bridge module
D5, D6 = 1N4148
D7, D8 = 5,6V Zener
D9, D10 = 1N4148
D11 = 1N4001 diode 1A
*Q1 = TIP31A, NPN transistor, no heatsink
*Q2 = TIP31A NPN transistor
Q3 = BC557, PNP transistor or BC327
*Q4 = Two paralleled 2N3055 NPN power transistors with 0.1 ohm, 1W emitter resistors each
*U1, U2, U3 = OPA445AP, operational amplifier
D12 = LED

"*" is a change from the original design.

 

[Kain]

I this is a little bit off topic but I want to do nice front pannel for the PSU and I wonder how I can project some writting on alumunium pannel... I was thinking of doing it in the same way as some of us do the PCB - tonner transfer. However, if I do so I don't know how strong the layer would be and if i won't loose it soon. Maybe I can apply some protective layer too ???? Any ideas?

 

[MP1]

There was some conversation about this topic here: http://www.electronics-lab.com/forum/index.php?board=15;action=display;threadid=951
gsmaster has a method that he has attached a photo.

MP

 

[Kain]

Hum, so he pretty much did what was thinking to do. I think after I transfer it to the aluminium I will use some transparent self-adhesive film to protect the image. Thanks tho

 

[Mash_Rishi1]

Hi to all electronic Guys!!!! Am new to this project. Hi AudoGuru it seems you are an expert in power supply designs. I would like to clear my elementry level doubt with all experts down there. Can I use a 15-0-15 V 5A transformer as a bridge circuit avoiding the centre tap? Could u plz attach a complete modofied circuit of this voltage regulator?

 

[ante1]

Mash,

A 15-0-15V transformer can be used the same way as a 30V transformer just don

 

[audioguru2]

Hi Mash,
Welcome to our forum.
Yeah, your transformer is fine for this 3A-DC power supply.
I am sorry that I can't revise the schematic, since I cannot manipulate GIF images. There isn't much difference, just an added 2N3055 and emitter resistors for each one, as shown earlier. Also, the emitter of Q1 should connect to ground, instead of the negative supply. Maybe someone will make these simple changes to the schematic for us.
The PCB also needs simple changes for the different pin-out for Q1 and Q2, and moving Q1's emitter as above.
The revised parts list has been given recently here. ;D

 

[Mash_Rishi1]

Thanks to Ante & Audioguru for your lightining fast replays.
Am assembling the whole thing on a veroboard. Let u all guys know once am done.

 

[Kain]

Ok, now I got really weird problem. As I posted earlier in this forum:
http://www.electronics-lab.com/forum/index.php?board=2;action=display;threadid=128;start=120

I'm trying to use digital panel meters for this PSU project. Everything seemed to be alright untill I tried to measure voltage from any power supply. What I mean is that these digital panels work fine when I measure potential from a battery, for example. However, once I hook it up to transformer based PSU it freaks out - it shows bogus numbers that fluctuate all over the scale. The weird thing is that even if I don't hook it up the voltmeter starts fluctuating a little bit. I powered up the panel as shown on the diagram by 9V battery. Any idea what could possibly cause this? ???

 

[ante1]

Kain,

Try a capacitor connected in parallel with the input to see if the value stabilizes. Use an electrolytic 10

 

[Kain]

Ante, I already tried this, and just to make sure I did it once again with no improvement. I tried cap in the iput before the voltage devider as well as after the devider - no change at all. I wonder how the unit would work if I hook it up in the other way - I mean powered by +-5V. I see it has a common ground with the inputs which might turn out to be the solution. What do you think about it? ???

 

[ante1]

Kain,

Yes, try it and let us know.

Ante :

 

[Kain]

Ok, I managed to fix it finally. The solution was as I suspected - common ground. I used the same transformer as for the PSU and made zener stabilized +-5V with mid point output, and I filtered the output potential with 1000mF/25V cap. Now it works absolutely stable - the measured value does't fluctuate even for one digit. ;D

 

[Dazza]

Hi all. I am new to electronics and I have built this power supply. Everything worked great except for the panel meters, it seems I'm not the only one. I tried everything I could think of which wasn't much. ended up adding to extra transformers, so at least now I have A power supply that I can use. I built the whole thing in an old stereo case and use the transformer from it. It doesn't look quite as bad as it sounds but there is enough room inside to swing a cat. If someone could help me with detailed information on solving the panel meter problem. so I can get rid of the two transformers would be very much appreciated. I can then put it into a proper case. Thanks in advance.

Dazza

 

[ante1]

Dazza,

Welcome to this forum.
Does your meters work properly with the extra transformers?

Ante :

 

[Dazza]

Thanks for your reply. The panel meters work very well. I would just prefer to make it more compact, and I want to incorporate a previous project I made from electronic lads(3-30 V/2.5 A Stabilized power supply). this is probably going to be one of my most used piece of equipment. So I would like to make it as good as a can.

 

[ante1]

Have you tried to supply both meters from one extra transformer?

Ante :