LM338 battery charager help

[aruna1]

hi i made this circuit(taken from http://www.talkingelectronics.com/projects/ChargingNiMH/ChargingNiMH.html),but doesnt seems to work.as i know voltage drop in R should be 1.2v, but in my circuit its about 4V, i tried R values from 1 ohm to 100 ohm,but couldnt get the circuit working,when using 1 ohm current drain was about 2.45A.
my input is from 12V-0V-12V transformer(24V dc using rectifier bridge) and target is charging a 12V 1500mAh NiMH battery pack.
any ideas?
thanks

[waltr]

24V dc using rectifier bridge

Do you have a filter cap after the rectifier?

[aruna1]

yes,220uf

[billhowl]

You may like to try this circuit taken from the datasheet, which limit both voltages and currents to charge the battery. or you can take a look on other charger circuit in the datasheet.
http://www.national.com/mpf/LM/LM338.html

[Pratheek]

The LM317 is a linear regulator so it will need an input voltage which is greater than the required output voltage by 2V.

So if you need a 12V output, you will need atleast 14V at the input pin.