ac adapter for an hp and digital camera

[SAV]

Hi,

I want to make an ac adapter for my HP 48g+ and a digital camera, the HP works with 4.5V DC given by 3 AAA batteries and the Digital camera operate under 3V DC, but it has a maxium power dissipation of 3W.

I want to know some consigerations for my design, i was thinking to use the tipical configuration with a transformator, rectifier,filter,regulator,etc. The ac adapters could be different for the two instruments. I want to be sure about the correct funcionality of this circuit before plug it into the devices, i don't want to make them any damage. Thanks for the help.

 

[usernam]

Hi,
try this link

http://www.eleinmec.com/article.asp?16

Some points to note about this circuit are
* Input voltage to the 7805 should be atleast 10V.
* Drop across each of the diodes is about 1V so be sure to use a transformer which gives an LV side voltage of about 12V or more.
* Smoothing capacitor should be high enough. (470 microfarad is a convenient value.)

To obtain 3 and 4.5V you can use a voltage divider after obtaining 5V output from the above circuit.

 

[batdin]

Hi,
I have recently made an adapter for a Kodak camera.It was 3V,3A adapter using the one-chip flyback SMPS TNY266.It worked very well and could be easily switched from one output voltage to another by simply changing the feedback circuit.Efficiency was excellent but I had to read very carefully some datasheets beforehand.
Everything can be found here: **broken link removed**