Hi! I’m working on a robotic arm that works with 3 servos. The servos that I’m using are MG995, and the board is an Arduino UNO R3. The question is: How can I power the servos?
I’ve tried with the 5v usb port, but they just tremble. Then I’ve tried with the 5v USB port and a 9v battery connected to the Arduino, but they keep trembling How can I power them properly so they can work?
PD: sorry for my bad english 
Hi,
It is not a good idea to power the servos from the 5V USB port as a standard USB port will provide 500mA and 3 RC servos like the MG995 could consume more than 500mA.
You can use an Arduino Shield like this one. This way, you can directly connect your servos to the shield. You can power your servos + Arduino by attaching a 5V power supply through the screw terminal on the Shield.
A Wall Adapter Power Supply - 5VDC 2A should be able to provide enough current to your Arduino + Servos. You can use this 2.1mm Barrel Jack to terminal and 2 M/M jumper wires to connect the wall adapter to the shield.