Need some help clarifying what controls the voltaged to a servo
 

I see some Servos offer two different input voltage and it changes the speed/TQ of the output.

I did a search on here about it and I wanted to make sure I understood it

The ESC controsl the power to the servo at x voltage. That x voltage is the controlling factor on what voltage the servo see's to pick the output 4.8v/6.0v

So the internal BEC ( if equipped) or a external BEC controls the voltage to the Servo ?

Sorry I am kind of new to the game on electronics on the cars

Your ESC's internal bec supplies the reciever and therefore the servo in a normal setup

Where the requirements (amp draw) of the servo are too big, people install an external bec

External bec's can supply a higher stable voltage and higher amp draw than most ESC's

Cheers

awesome, thank you