Servo voltage?

I've got a 9g micro servo that runs on 3-7.2V. It runs perfectly on the arduino's 5V, when I've got it hooked up to the "knob" circuit. (http://arduino.cc/en/Tutorial/Knob) I tried plugging in a USB and AAA power source that I made and tested with the multimeter at 6.5 V. The servo twitches violently and overheats quick. (It may be ruined at this point, but I have more) Is there something I'm missing? I simply removed the two wires from arduino's 5V and ground and replaced them with my two wires, correct polarity.

Did you connect the battery positive to the servo positive, the arduino pin to the servo signal, and battery and servo and arduino ground together?

Battery, servo, AND arduino grounds connected? I'll need to try that. Thanks ;)

Made a little picture

This is also using the battery as power supply for the arduino (it won't run on the 3V provided like this), but you can easily use usb to power the arduino, and then the battery to power the servo

This is how you should do it, with usb powering the arduino, and the battery powering the servo

Thanks, worked perfectly ;) The other servo is certainly fried, but I've got 5 others and I've learned my lesson xD thanks ;)