How to generate DC 3V and 3mA current from 230V AC supply?
But once you have the walwart, you can easily add your own regulation. Either with a linear regulator (a little easier) or a switching regulator (just slightly harder to do. In fact one of my very first "large" projects. I used a linear regulator. But with some of the new chips, it is actually pretty easy to design a switching regulator. TI really makes it easy for the design challenged with their online calculators.The one thing with the supply in the link is it is a linear supply and generally are unregulated, the switching types are usually well regulated if you can get one in 3vdc.
Max.
<snip>How to generate DC 3V and 3mA current from 230V AC supply?
The current will be decided by the load, you don't need a resistor, if 3v output?around 3V (3 or 3.3V I cant remember) use resistor to drop to 3mA
Yes sorry I wasnt clear, I didnt understand what exactly he meant by 3mA, for example does he want to say run a led at 3mA, the phone charger will handle upto about 150mA (could be alot more I just dont remember), so maybe he needs a limit, I was going to say do a constant current driver, but he probably dosnt need that. I made assumptions and guess's, hence the resistor.The current will be decided by the load, you don't need a resistor, if 3v output?
Max.
Not true. At least according to the rules around here. A transformer is always needed to be safe.For only 3mA - and if you don't need mains isolation,
You could be confused about the 3V @ 3mA power supply.
In a power supply you control either the voltage or the current, not both at the same time.
Which do you want, 3V or 3mA?
If you've got 3.3V and want 3.0V, the forward volt drop of a Shottky barrier diode will take care of somewhere close to the unwanted 0.3V.an old Nokia phone charger, I have one that is around 3V (3 or 3.3V I cant remember) use resistor to drop to 3mA