AC to DC converter with selectable voltages?

[anatech]

Audiophilenoob, what is a DC transformer?

That's what has been bothering me since post #2. Studing core saturation effects?

-Chris

 

[Audiophilenoob]

I'm trying to figure out what you are trying to accomplish. I can't even begin to suggest anything to help you with this much information.

What I have so far is you need a DC supply at high current with mV precision. Tall order because the noise may be more than 1mV at higher currents. Tempco and connection resistance in the mV region become important, as does thermocouple potentials.

You may possibly be beyond a primary laboratory's ability to quantify the measurement.

-Chris

I need to to test something in chemistry...

it's to find the voltage a certain substance electolyizes...

I was trying to keep it audio related to keep interest up

sorry for the deception...

the goal is to have this low voltage attenuation as the reaction could happen anywhere from 1mv-4v... I need to find the exact Mv it occurs... and math doesn't get me very far in finding it

I assume that I won't get much help now that it's not audio related

 

[Audiophilenoob]

Audiophilenoob, what is a DC transformer?

I'm not sure... I figured some type of transformer DC type would be needed to allow this kind of attenuation...

if they don't exist... I apologize for my lack of knowledge

 

[anatech]

Transformers depend on a constantly changing flux to operate. Therefore, no DC transformer exists.

When a substance electolyizes, does it suddenly draw a lot of current? I don't know much at all about this. I am thinking lab quality voltage references, like a Data Precision. You know, a Fluke 5520 calibrator may do what you need quite well. It is capable of high current and mV control. A Fluke 5500A may be enough. I trust these more than Wavetek.

-Chris

 

[Audiophilenoob]

Transformers depend on a constantly changing flux to operate. Therefore, no DC transformer exists.

When a substance electolyizes, does it suddenly draw a lot of current? I don't know much at all about this. I am thinking lab quality voltage references, like a Data Precision. You know, a Fluke 5520 calibrator may do what you need quite well. It is capable of high current and mV control. A Fluke 5500A may be enough. I trust these more than Wavetek.

-Chris

a substance electrolyzies at a certain voltage and as you increase current it will cause more and more electroylsis and greatly increased speeds... exponientally IIRC

a fluke 5520 is just the calibrator or is it the entire unit with PSU? or would i need to make a PSU?

thanks

 

[peranders]

I think you may have to study chemistry a bit more because the little I know says that nothing happens under 0,5 volts or so and the current are small. You could surely use an ordinary lab power supply. If your budget is a 800 W 30 A PS you can go buying a ready made unit.

May I ask why you want to do this experiment? I'll suspect that you are heavily dreaming about needed equipment.

 

[anatech]

The Fluke 5500A and 5520 are selfcontained calibrators that should do everything you are looking for. Might be overkill but are sure to work. They are found in instrument calibration labs.

-Chris

 

[sss]

the amperage should also increase as you decrease in voltage (same total wattage I guess)...

how is that gonna happen?
if u got a constant load the current will decrease with the voltage

some kind of negative impedance load?

 

[Audiophilenoob]

I think you may have to study chemistry a bit more because the little I know says that nothing happens under 0,5 volts or so and the current are small. You could surely use an ordinary lab power supply. If your budget is a 800 W 30 A PS you can go buying a ready made unit.

May I ask why you want to do this experiment? I'll suspect that you are heavily dreaming about needed equipment.

the voltages is far lower than with water

water is 1.7v in sulfuric alkaline and then just raise the current...

the problem is I don't know the voltage this occurs... in fact I can't find it out... I've searched everywhere and to my knowledge I'm the only person to ever attempt electolyizing this liquid...

the problem is wasting voltage... I think I could just build a 0.5v PSU with high amperage and it would work fine... this isn't a problem at all and very simple

but if there's even 0.1v of wasted voltage it brings down the whole efficency of the system dramatically

I hear that the voltage is around 0.07v that this occurs... but I'm not sure...

if I could figure it out some other way besides a variable power supply I would love to figure it out