# How to test how much current 9 servos can draw at a time? [closed]

Plus how should I use a multimeter to test it?

P. S. Really sorry for a noon question.

• Welcome to Robotics, confused_engineer. I'm closing this because it's not a robotics question - it belongs at Electrical Engineering. That said, the easiest way to do this is to just look up the 'Absolute Maximum Ratings' and find current. If that's not possible (harvested servos, etc.) you should follow @BenceKaulics' post, with the caveat that you need to get the servo to draw its peak current (stall). Oct 7 '16 at 18:57
• I also wonder, in your system, if it is possible to drive all 9 servos at peak torque. Often you'll find, for a manipulator arm, that this scenario doesn't make sense. But that depends on the system, and we don't have any information about that. Oct 8 '16 at 17:37

I assume that all the servos are identical, so it is enough to measure only one, and multiply the result by 9.

The best would be if you could use a lab bench variable power supply, like this. With one of these you do not even need a multimeter as these power supplies are able to measure the current they are sourcing. You simply just need to connect the "+" to the VCC of the servo and the "-" to the GND of the servo, set the output votlage and check the current.

If you do not have access to such a device then the following setup should be used.

As you can see the multimeter should be connected in series with the servo to measure its current.

You should connect to multimeter cables as it can be seen on the following image.

(source: engineersgarage.com)

You are going to measure DC current, and possibly it will be over 1 A, so choose the measurement range accordingly. The red cable goes to the power supply Vout ("+") and the black cable goes to the VCC of the servo.

Make sure the all of your wires are suitable for the measurement, they won't melt or catch fire because of large currents. And if exists, check the datasheet of the servos about its current comsuption, just to know what range to expect.

• Hello thanks man I really appreciate your help, I got the right answer. I do apologize as it was a really noob question but I am more smarter now and much closer to finishing up my project. Thank you bence kaulics Oct 8 '16 at 22:29