This question may sound senseless but I am novice, just looking for clarification. My Cordless phone has a Wall wart AC Power Adapter rated at 9v 500mAh. As far as replacement is concerned, does output power only matters or we have to be specific with ratings also? Like a 4.5V 1A adapter output will also be 4.5W as original rating. I have read in this forum that higher current rating may not matter but higher voltage may damage. Also, I have heard that SMPS based supplies senses the actual load and outputs accordingly. Please correct me.