DC power Supplies

Taz · Mon Mar 14, 2005 10:10 am

I would like to start a thread on DC power supplies
Does anyone know any good sources. Has SWIM understands it Volts are the amount of the current and the amps are the speed at which the volts are delivered and in electrolysis the actual productivity of the procedure is directly proportional to the amps.I am also lookig for a good
source for dc power.And any info on the minimum amount of volts and amps or a good source for a general purpose electrolysis set up? Would be
appreciated.

IndoleAmine · Dreamreader Deluxe

Yes - voltage means "intensity" and ampere is density of electrons.
Both can be conveniently regulated with a standard adjustable DC power supply found in electronics shacks or similar stores. Cost: about 50 bucks, you can regulate voltage and based on that selection you can regulate the amperes.

Minimum volts it should be able to deliver is around 5-7 V, and enough power is always good to have - 500 mA is the minimum.

But to be honest, I'm not that experienced with electrolysis reactions...

i_a

bio · Working Bee

Most electrolytic reactions these days run at constant current until the required number of Faradays are passed. Constant potential (voltage) is sometimes used as is variable voltage,

If your power supply does not have a constant current feature (must have it) then depending on the controller IC it is usually as simple as putting a series resistor and moving the sense line downstram of it.

Pick up a LM317 voltage regulator IC (3 wires) add the resistor and a few other parts and your in biz. Go to National Semiconductors website and look at the Application Notes for schematics for constant current regulators made with the LM317 voltage regulator. It's really quite simple although you may need a friend to help you if electrically deprived. A decent current regulator of 3-5 amps ain't cheap (hundreds $) but you can pick up the 317 for just a couple bucks and needs very few additional components. They come to 5amps and can be used as a driver for larger supplies.

Taz · Fri Mar 25, 2005 12:24 am

Thanks for the help Swim finally settled on a power
supply it was a hard descision not knowing much about
them but this is what he settled on he ordered it today just hope it will do any electrolis I come across I may want try

[(Note: since your real identity may be easily tracked when you link to ebay items you bought, this is NOT cool - so I removed the link and hosted the image somewhere else (see below) - since it is a commercial, advertising image, your anonymity should be kept this way....
indole_amine)

Rolling Eyes

Any opinions are did I just blow some $ for nothing Shocked

IndoleAmine · Dreamreader Deluxe

Wow, now THAT's what I call a decent adjustable lab DC power supply!! Exclamation

IndoleAmine · Dreamreader Deluxe

BTW you noticed the small LEDs labelled "C.C." and "C.V."?

Either one or the other of them will always be shining (depending on in which chronological order you use the regulating knobs I would guess), but never both at the same time (or it is capable of melting wires very easily Laughing

).

I would bet that this thing can deliver either a constant voltage or a constant current, and in your case you will want to use "C.C." operation mode (see bios comment)...

i_a

MargaretThatcher · Fri Mar 25, 2005 11:51 pm

I don't think electrochemical synthesis is always so straight forward. Many reactions run at a constant voltage measured by a reference electrode wrt the working electrode.

IndoleAmine · Dreamreader Deluxe

The working electrode acts as measuring electrode too, I thought?
And since this DC power supply has both amp- and voltmeter buit in, you can quite well tell how much faradays will pass through the electrode in a certain amnt. of time, as soon as you know the surface of the electrode, no? I guess you are talking about electrolytic rxns involving dissolving electrodes? Then the surface would become constantly smaller of course, and a reference electrode made of inert material would be needed...

i_a

Taz · Sat Mar 26, 2005 6:15 am

Acording to the manufactor you adjust the volts and

amp at the same time in any configuration one pleases.example it will do 0 to 30 in very small incrementsat 1 amp all the way to 20 in 1/10 increasements Swim emailed them already anyway
Swim will be able to let you know in a couple of weeks and Swim just got his copy of SOMM 7 today and according to what Swim is reading this is exactly what is needed.A steady supply just like this one is described.as for as melting wires goes Swim does't know swim guess's that would depend on how it was configured and the gauge of the wires. Twisted Evil

Thanks for removing the link swim guesses he wasn't thinking when he posted that. Sad

MargaretThatcher · Mon Mar 28, 2005 6:15 am

This pdf has a lot of information related to electrochemistry. If you have an exact specification to follow, then fine, but most of the patents are vague on the exact details. If you want to measure the PD of the working electrode, what are you measuring it relative to? Wrt the counter electrode is pretty meaningless. Normally a reference electrode is used.

There are many factors involved in an electrochemical cell. Without exact details, you will have to tinker a lot, and this is where a reference electrode and potentiostat or similar would come in useful. At least with some equipment, you can get a voltage/current graph and look for the steps where the possible reactions occur.

Edit: Ahh, I can't upload pdfs to ImageShack. I'll look for somewhere else to host it.

Edit: This is the boy

http://rapidshare.de/files/1041755/potentiostat_design.pdf.html

stratosphere · Wed Apr 20, 2005 10:17 pm

to make a simple "low precision" dc volatage supply all you need is a transformer, full wave bridge, capacitor, transistor, heat sink and variable resistor, all are available at radio shack or similiar parts store and together should cost under $50.

basically you can use the same parts to make either a constant current supply or constant voltage supply, it just depends on how you wire them together.

unfortunatly you need a host to post pics and describing it in words would be a waste of time, but if your interested in the schematic for these just message me.