Okay so recently i watched a great video and read a paper on anodizing mild steel, Paper found here https://pdfs.semanticscholar.org/c532/91aeb43b2ff35b04d88ee973e8df58e42fca.pdf
The quick and dirty, by placing a piece of mild steel in a warm bath of either 50% KOH or 50% NaOH in 50% distilled water. then clipping that piece of mild steel to the positive of a low voltage , low amp power source, & the negative up to apiece of iron. A magnetite oxide layer then forms on the mild steel. Acting like a rust proof coating.
As the chemicals im using are relatively caustic , The experiments are done outside and the anodizing process takes about 5 minutes. So Something portable makes good sense to me.
my main issue is the set up is acting abit like a fuel cell so having a highly conductive solution plus having amp draw which is determined on how close the piece of iron and mild steel are apart. there needs to be some sort of current regulation. The circuit below took my interest.
My questions -
1) it says its a 6v charger but when the resistors R1 & R2 are worked out its 6.9v. Is there some voltage drop from the npn current regulator. 0.6v would bring it down to 6.3v
2) If that is the case could i change the voltage to just over 4v by just changing R1 500ohms - R2 1.5K - output 5V , Minus 0.6 = 4.4V
3) If i wanted to set the current to 250ma would R = 0.6/0.25 = 2.4ohms be correct for R3.
Any help would be appreciated.
Kind regards,
Rick
The quick and dirty, by placing a piece of mild steel in a warm bath of either 50% KOH or 50% NaOH in 50% distilled water. then clipping that piece of mild steel to the positive of a low voltage , low amp power source, & the negative up to apiece of iron. A magnetite oxide layer then forms on the mild steel. Acting like a rust proof coating.
As the chemicals im using are relatively caustic , The experiments are done outside and the anodizing process takes about 5 minutes. So Something portable makes good sense to me.
my main issue is the set up is acting abit like a fuel cell so having a highly conductive solution plus having amp draw which is determined on how close the piece of iron and mild steel are apart. there needs to be some sort of current regulation. The circuit below took my interest.
My questions -
1) it says its a 6v charger but when the resistors R1 & R2 are worked out its 6.9v. Is there some voltage drop from the npn current regulator. 0.6v would bring it down to 6.3v
2) If that is the case could i change the voltage to just over 4v by just changing R1 500ohms - R2 1.5K - output 5V , Minus 0.6 = 4.4V
3) If i wanted to set the current to 250ma would R = 0.6/0.25 = 2.4ohms be correct for R3.
Any help would be appreciated.
Kind regards,
Rick