My arduino is UNO (and have another mini pro) it has 3.22v output i have done short test with it
So my motor is 3.22v and 16.1mA
I need 200ohm resistor exactly (0.01% tolerance
With 3.3v, the motor should be fine without a resistor without exceeding the current limits.
But if you do use a resistor, the value does not need to be that precise e.g. you can use 150 ohms or 220 ohms.
Now about transistor, i have read about it as it is stable output regulator regarding to middle pin input.
Sorry, not following you here.
Basically the current on the base (center pin) controls the (usually higher) current between the emitter in the collector.
Actually i don`t have any transistors now, but i will get some nearly, or i will grab into some old home electronics
Definitely something worth having and 2n2222 are really cheap.
Do we need transistor to prevent interchangeness of amperage by motor? because if i block motor rotation the amperage increases up to 140mA. I have read about transistors but there are were not any equation or any rule for it, just explanation. can ou forward me to right direction to understand transistors.
That means the motor stall current is 140ma. A 2N2222 should be able to handle that.
One more question, you said 2n2222 transistor which resistance is included, and it is 10k so do i need to subtract this resistance and get ohm for separate resistor regarding to transistor`s internal resistor? do all transistors has resistor inside or it is just resistance of transistor itself?
Very few transistors have resistors inside. You need a base resistor somewhere between 220 ohms and 100K depending on the current you need to switch. Without a proper base resistor, the transistor will draw too much current and risk damaging your Arduino pin.