AC/DC Adapter.

Please I want an help to do my project on AC/DC Adapter with 9wpower, 3v/12voutputDC, 110/220vinput, 500mAcurrent.

Posted by Ben (americanaraffiamma@yahoo.com) on 23/08/2005, at 16:16 GMT

AC/DC Adaptor

If unsure about a power supply I would by a Uniross/Maplin Electronics linear adaptor (VN10L Maplin Order Code) that uses the LM317 voltage regulator ic. The mains transformer you require will have 2 120v primary windings rated minimum of 12/15 VA (watts) . However there is a snag that the lower output voltages will involve having a greater voltage difference across the regulator ic which limits the output current draw when maximum power dissapation (15watts) is reached, unless the transformer has a tapped secondary winding that is operated in sync with the selected output voltage. The supplies mentioned at the beginning have this feature.

Posted by Robert Neill (varient412@yahoo.co.uk) on 11/03/2010, at 22:42 GMT

AC/DC Adapter.

Incidently I have one adaptor with the casing broken open to use as a guide when developing your supply. LM317T voltage calculation Vout = 1.25*Rvselection/Rref-feedback- given as 220R-240R ohms.

Posted by Robert Neill (varient412@yahoo.co.uk) on 12/03/2010, at 10:05 GMT

Getting a power supply.

You can get an adapter from a online store called rapid. Ebay is also good ut it may be a bit low quality. you can also make one using the instructions on this website. THe maplins website also has a helpful section on getting a power supply

Posted by ariel on 06/01/2011, at 11:32 GMT