I am making a simple robotic arm with atmega8 using two servos(two joints), I am using Software PWM of AVR and it is working damn perfectly for one servo. Then i attach another servo and both does random movements (sometimes don't move, sometimes out-of-bound), then while power on if i detach one then the other attached one starts to work correctly.. I think this is some voltage or current problem? Btw i am powering my board with computer usb port 5v. No need to ask for code because it is ok because one servo does well until other joins. A little bit same question is asked by someone here but no one answered there so i wrote my own..
EDIT(1): Upon getting answers that i have to connect external power supply for servos, i think making a small external circuit would work like this here, would this work?