Ah. What is root power supply going to be?

I'm thinking the guts of a non automatic vehicle battery charger like this one...

 

Steve as per your request. This circuit can also be used for a bench power supply, using 10 turn pots it will add a nice touch. I suggest not using actual zeners better to use something likr the LM285-2.5.

 

Pich, that is excellent ! Thank You. Is there any reason I can't use the components from the charger I posted as the supply to this circuit ? I can't imagine why not.

Ten turn pots and digital or analog meters for Volts and Amps will make a great plating supply.


Thanks again,

Steve

 

No problem using a battery charger, need to beef up the C2 to about 4700uf and you will need to use the LM 358 that way there won't be any need for -12volts. The voltage control will still be able to adjust close to 0 volts.

 

So I can make pin 4 of the LM358 ground and tie the 5 volt inputs to 12 volts, use the LM285-2.5's in place of the Zeners, change C2 and be good right ?

 

Yes, the LM 358 will allow sensing near ground, running pin 4 at ground potential should be OK. Let us know how you make out.

 

Great, Unless you know of any reason not to at this point, I'll go ahead and layout the PCB for this in Eagle (with wide traces where needed) and then I'll post the layout here.

I'll definitely report back with how it works out.

Thanks very much,

Steve

 

My exp with the lm358 was it kept reaching overload and safety features would shutdown never ove 3,5 amps sometimes around 2 75 if jumped to quickly the only method I found to achieve the 8-15 amp at 9-12v was oh man i cant remember the #s was a tin can though I tried 5 different heatsinks on it ended up with one too hot at 6 amps the next around 11 then adding 1.5 lbs aluminum was my ratio to increase aprox 1 amp.
was very informative for me but fans would have been so much simpler.
I can find that unit if ou need/want the numbers.

 

What about the PS pictured below ? How does it vary the current ?

It doesn't vary the current, it LIMITS the amount of current it allows to flow out.

 

dear friends

for a constant current we can use lm317 as constant current source!

one of its applications is in charging batteries.

you can see this application in lm317 datasheet.

it is very simple.

 

Hi All,

My first post here. I have built many circuits and I also program PIC's. I've etched, ironed on, and milled PCB's for my projects, ETC,ETC.

And I've built many power supplies using LM78xx and LM317's including a three output unit on my bench that has separate outputs for 5vdc,12vdc and adjustable 1.2 to 20 vdc. All of these are about 1.5 amps max with heatsinks and the adjustable one has digital LED displays for volt and current.

I say all this so you guys will know I'm not a complete n00b but I have never built a supply with adjustable current output so I'll explain my application below.

I need to build a supply for an electroplating setup with the following requirements...

Voltage adjustable from ~1.2 to ~10 VDC
Current adjustable from ~0 to ~6 Amps

This will never be used for any electronics applications. I am planning to get a high current car battery charger and use the transformer and other parts of it for this PS.

I expect to heatsink and use at least one fan as well and I'll have displays for V and A of course.

So my question (finally) is, can you please give me some advice on what IC I should use for the adjustable current and/or a schematic of one ?

I apologize for being long winded on all this, if I've left any info out, let me know and thanks for any help,

Steve