Perhaps but I prefer this representation:
Arduino servo signal pin----------------.--------------[ servo]
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[4.7 kohm resistor]
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GND
Perhaps but I prefer this representation:
Why ?
Because in schematics we like to see power above, ground below and everything else to the left and right. so if you are switching a motor , the motor power is above, then below that is the motor and below that is the transistor and below that is ground so if you trace the path of the current it appears to flow from above (power) to below (ground). You can scramble it up nine ways from sunday and still have it electrically correct but we are used to seeing it a certain way and we prefer to keep it that way. uC on the left, peripherals on the right (why ? no reason other than that's what we are used to ) HERE IS THE SERVO (IT HAS THREE WIRES (RED , BLK, ORN (OR WHITE))
The first two are power (4.5-6Vdc)
Let's forget about the red & blk power wires and just talk about the orange (or white or yellow) signal wire) Robin2 suggest the 4700 ohm resistor from this signal wire to GND (ground) to BLEED off any excess voltage that might cause the servo to move. You can think of it as a cork in a faucet to keep it from dripping, (crude analogy) but basically if guarantees 0V on the servo PWM input . Without a PWM signal , the servo can't move because it only responds to PWM signals . The BLEED resistor which in our world we call a "pullDOWN " resistor, consists of a resistance value low enough to pull the signal down but high enough to not prevent the arduino I/O signal from working when it is present.