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0-30V Stabilized Power Supply


redwire

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I was observing schematic of this power supply unit, and I would like to know how does it actually works? I can lightly understand how does it works, but can not apprehend details. There is a general description of this P.S.U. but, simply I would like to know more details. Is there any DETAILED description of this P.S.U.? I am especially interested about U1 voltage reference. I don`t understand how output of U1 gradually increases? What makes potential difference on the U1 plus and minus terminals to force output rise?
Any additional explanation about this P.S.U. is welcome (some site, text, reply, picture, pdf document...).
Best regards,
ing. Sarkezi Michal.
[email protected]

P.S. sorry for my bad english. :)

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Is there any DETAILED description of this P.S.U.? I am especially interested about U1 voltage reference. I don`t understand how output of U1 gradually increases? What makes potential difference on the U1 plus and minus terminals to force output rise?

When power is applied, D8 does not have enough voltage to conduct but the opamp has positive feedback from R5 nand R6 so it greatly amplifies the noise in the opamp until the output voltage reaches about 10V when the zener diode D8 begins to conduct.
When pin 2 rises to +5.6V then the output is 11.2V.
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so.... i'm back again to be annoying ;D
to turn my psu into the 5A variant the transformer has to be 2x30V at how much amperes.

I don't know why you have two 30V windings on your transformer.
30V makes a peak voltage of 42.4V that feeds the bridge rectifier and main filter capacitor. If the load on the project is 5A then its max power is 42.4V x 5A= 212W.

Therefore the 30V transformer must be rated at 212VA or 7.07A or it will get too hot.
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So I decided to throw D15 away and replaced it with a peace of wire. Now I am able to get 30V with 3A.
If someone has the same problem as I (The rectifier voltage is to high for the oamps with 44V) you can use D15 which should have only as much voltage as you need to get under the 44V. The voltage in my circuit is about 39.6V - 44V and nothing is damaged.


I have just started with this project and am reading up on all the alternations/changes that have been made but I can't find "D15". Am I missing something in the schematics ?
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I don't know why you have two 30V windings on your transformer.
30V makes a peak voltage of 42.4V that feeds the bridge rectifier and main filter capacitor. If the load on the project is 5A then its max power is 42.4V x 5A= 212W.

Therefore the 30V transformer must be rated at 212VA or 7.07A or it will get too hot.


7 A..............i understand a bit expensive to order but ok
i made a mistake writing the 2x30 i was thinking about something else and it doesn't have anything to do with electronics ;D
was a way for me to say that i have 2 psu
tanks!
good luck! :D
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I have just started with this project and am reading up on all the alternations/changes that have been made but I can't find "D15". Am I missing something in the schematics?

I don't know whose schematic has D15. Mine shows a new 10V/1W zener diode that reduces the supply voltage to U3 but it does not have a part number and is missing on my latest parts list.
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hello!
i am also thinking about making it as my project for this semester. what i want to know is should i use the info provided in the .rar file by redwire on the first page of this discussion(all the info was updated on 30 dec 09). And does any one have single side PCB layout? If not then could anyone give some tip about making double sided  pcb and how to print redwires circuit from EAGLE(i don't know how to use that software)
also i dont know how you solder things on double PCB. and redwires design (the picture of the finalized circuit) looks on single sided PCB. is it so?

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shoaibasghar - i am busy making the PSU myself. My suggestion, if you have not got the facility to make DSPCB, is to route the board in Eagle on the copper side only and to use top layer tracks as "jumpers". This works well. They must be straight however.


u mean to say that i should make only one sided board and connect the upper sides by wires instead?
if so will normal jumper wires do or i have to use thick ones. and which schematics etc are you using? one on first page by redwire?
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u mean to say that i should make only one sided board and connect the upper sides by wires instead?

Exactly.That is how i do it all the time for making prototypes. You just have to remember to keep the top layer "jumpers" straight else you will be soldering in some weird looking wires. If you have to go around a corner then use top-straight, bottom-angled and the top-straight again.

Also remember to make the vias for the top layer with at least a 0.8mm hole size and 1.6mm diameter else you will destroy the via when you drill it.....

if so will normal jumper wires do or i have to use thick ones.

normal UTP core is what I use. Only need heavy duty wire for high current tracks.

and which schematics etc are you using? one on first page by redwire?

I have down loaded the latest, the one with all the RED text. I havn't got much further other than to redo the schematic in Eagle, busy now with routing tracks from the netlist
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i planning to make a voltmeter and ammeter for this power supply, i will step down the output voltage from the power supply and step up the voltage from the shunt resistor using two opamps configured as differential amplifier.

is the -1.3v from the power supply enough for the meter opamps?

i will use tle2141 for the meter.

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I have just finished a double sidet pcb using the scematics from redwire, i have modifiet it a little, making the routes and soldering points a little wider to make it a bit more DIY friently, i used the laser print transfer metod from this link http://www.riccibitti.com/pcb/pcb.htm its a bit of a PITA to solder ic-sockets and some of the other components without "eyelet"connector pipes. i have the scematics on a PDF file (front, back and components) but i dont know how to upload them to the site

Holt

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