Hi Tino and Electron, Thanks. The ESR of the used cap is 100 ohm @ 1kHz. Now, the problem I see with the circuit given by some of the guys, the simple diode, is that the device will not detect the low voltage condition... I think I should better go and use the DS1302-..... regards Mauricio -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist