h-bridge

Using Arduino Project Guidance
#1

Hello fellows,

I have bought an h-bridge (TI SN754410) in order to control my DC-motor back+forward and it works perfectly by the way, but I still have a few concerns. I basically built my circuit after the instructions on the picture you can see below (without the switch, I only use the h-bridge).
Questions => (1) As external power-supply for my engine I use a 8.4 volts or 11.1 volts battery and the whole battery is basically attached to the Arduino, is it? However if I run the engine at full speed, does the Arduino withstand all the current-flow without getting damaged because there are no resistors (see picture). (2) What´s the maxium external voltage I could apply not to damage the Arduino (the h-bridge can stand up to 36V, 1A) => for instance if I apply this voltage, does the Arduino not get damaged?
Can I run my motor safely at constant full speed with 8.4 volts and the configuration on the picture?

LabDCMotorH-Bridge9V_bb.png

#2

p.s. does the Arduino has internal resistors, I´m sure the current flow is not infinite, haha and is the value of them determineable?

#3

Is the battery connected to Vin to power the arduino, and In Parallel to the 754410?
With Arduino Gnd connected to Battery -?
Then the Arduino will only draw the current it needs, will supply the control pins with the voltage current they need. The current thru the motor does enter the arduino.
However - large current surges, such as when the motor starts up quick, or is stalled (like a car stopping against a wall), can cause a temporary voltage drop from the battery and result in a processor restart.
Hence processor power is usually suplied indepenedent of motor power.

#4

Nope, my Arduino is powered seperately, but the rest is like on the picture.

#5

So do I need additional resistors or does this configuration work without having a broken Arduino?
thanks very much in advance!

#6