Hello, i have a problem regrading to servo motor connection. I used 9v super alkaline batery as a power supply for connect 3 servo motor (DF15MG) to Arduino Uno in parallel connection, then my laptop was shut down immediately. after that, i try used power bank (5v) as a power supply then my power bank was broken.my servo motor have 3 wires. for yellow,i connect to signal in pin 9,10 and 11in arduino. red wires connected to positive batery, brown wire grounded to negative batery and arduino. for your information, we did not used supply 5v from arduino. i connect arduino used usb to my laptop for monitoring purposed.i hope you can help me how to solve this problem... thank you.
Servos need high current. You should never power them from the Arduino 5V line, it cannot
supply enough current and you risk putting damaging spikes on to the Arduino's supply
which could fry it (and your laptop).
So separate supply for servos, budget 1A peak minimum per servo. Yours are high torque,
looks like they want 2 or 3A peak each.
Alkaline 9V batteries are 2 orders of magnitude too wimpy for what you want. They can provide
50mA reasonable well, start to really flake out above that. Think SLA or LiPo as power sourced.