Will this simple circuit Motors 1 be safe enough to control standard servo motor like Servo Analog HK15138 Standard ?
You are linking to 7 ciruits on one page that will control a motor.
And you are asking if that will do for a servo.
A servo is not a motor, although it has a motor in it.
You can control a servo direct from an Arduino pin.
But it is likely you need to use an external power supply.
Read my signoff.
I'm talking about the first and the simplest circuit in the linked page. Direct control from Arduino pin is not very safe, or so I was told. I just need some protection circuit.
Do you understand the difference between a motor and a servo ?
A servo is powered and has an external control signal.
That control signal tells the servo where to go, and the internal processor (either analog or digital) translates that and makes a motor run until it has reached that point.
This means the motor in the servo will not be directly connected to an output pin, just it's control signal.
But if it will make you feel better, you can use something like that first circuit.
Dump the diode, you don't need it.
Instead of the motor, connect a pull up resistor.
Connect the signal wire from the servo (probably the yellow one) to the point where the pull up resistor and the collector of the transistor.
Also do not try to control your servo as if it is a motor.
Use the servo library.
Some info about servos