Power Supply for Servos

Hello. I’m trying to build a Simple Robotic Arm. Just when i thought i was ready, i had forgotten about the power supply. Il’l be using about 4-5 Servos. I know I obviously need an external power supply. Since i have rechargeable 9V batteries i thought, why not use them. Since the Servos operate at around 5-6 volts, i thought maybe i could use a resistor to get down to the appropriate level. My question is, would this work, and what resistance will i need if so.The model of the Servos is, “SG90”. I know they’re not the best, but i think they’ll work. Thanks for your help.

DannyIsOnFire14:
Hello. I’m trying to build a Simple Robotic Arm. Just when i thought i was ready, i had forgotten about the power supply. Il’l be using about 4-5 Servos. I know I obviously need an external power supply. Since i have rechargeable 9V batteries i thought, why not use them. Since the Servos operate at around 5-6 volts, i thought maybe i could use a resistor to get down to the appropriate level. My question is, would this work, and what resistance will i need if so.The model of the Servos is, “SG90”. I know they’re not the best, but i think they’ll work. Thanks for your help.

You know the voltage drop using a resistor is entirely based on the current through the resistor. Since the starting current for a servo to begin moving is rather great and the current for the servo is much smaller once it is moving, the voltage drop will vary all over the place. The servo may not even be able to start moving.

Get an appropriate supply for the voltage and total starting current for the servos.

Paul

Buy a buck converter (step down) and adjust it to 5v, then connect it to your batteries. But a 9v bat might not handle the 5 servos at full power.

A resistor won't work. A step-down converter might work but first, what sort of rechargeable 9V batteries do you have? Many of the small PP3 types will not supply anywhere near enough current to run several servos.

It may be better to use 4 X AA rechargeable NiMH batteries instead.

Steve