how to convert power from the mains ?

[shyamgenious]

hey guys/gurls
this post is for my upcoming robot and i need to charge some very sensitve li-batteries with steady voltages.
how can i convert the electricity from the mains to useable battery voltage like some 9 volt??
do i use resistors? i need to test run my motors and need to check servoswith eltricity and am awaiting shipment so plz help to the earliest.

regards
shyamgeni

[waltr]

Do NOT use resistors as there will not be the isolation needed for safety. We don't want you to get electrocuted.

The easiest and cheapest is to buy a Wall Wart AC to DC power supply or use one from some electronic device that is now dead.

How much current at 9Volts do you need?

[shyamgenious]

Do NOT use resistors as there will not be the isolation needed for safety. We don't want you to get electrocuted.

The easiest and cheapest is to buy a Wall Wart AC to DC power supply or use one from some electronic device that is now dead.

How much current at 9Volts do you need?

i definitely dont wanna get electrocuted     but can you elaborate upon the term electronic devices?? do i get the conversion unit from electrical devices?as i have opened many electrical devices and have some experience is the wiry thingy used in battery chargers the ac-to-dc converter??i hav a big transformer exactly....il tell you tomorrow how many volts but till then plz answer my bove Qs
 
rgeards
shyamgeni