You should just use the circuit that I gave you and change the negative feedback, in order to get whatever voltage you want at the output (it wont be more than "12V" with "15V" power supply).

 

Have you adjusted R2 and R6 correctly?

 

Have you adjusted R2 and R6 correctly?

Yes

While changing R6 to one side fan is stopped and the other it's working in full speed, but On turning R2 to both extreme ends make fan to rotate at full speed and R5 have no effect on fan.

 

My point is that 15V isn't common where as 12V wall warts are. and the circuit also calls for 5V so it needs a VR for that. The reason why I liked the 642 is that it also has fan fault detection and will work with all the common PC/CPU/Powersupply fans out there. Looks like he's off on another direction anyway.

Probably the easiest approach would be using an Arduino Nano (<$10 list price, ~3 on ebay) and a few parts (vr, thermistor, transistor).

He doesnt needs a dual power supply, he needs "15V" on the "+" power supply and "0V" on the negative power supply. As the temperature increases (10mV per degree) the voltage will increase and if the DC motor is voltage controlled (not PWM) than it will just run.

 

I was considering lowering the power supply with 2 transistors (NPN, PNP) as a regulator. The "LM335" doesnt want much for powering itself. And the circuit was simple. All you do is input the signal from the temp sensor on the positive input and control the feedback resistor in order to set the speed for a given temperature.

I agree that the fault protection is missing and I havent used your chip, if you can give a tutorial I would be happy try if I can.

 

This is the chip that I use for a "12V" DC motor. But its only for changing the rotation direction.

 

Problem solved

It's because 555 chip is damaged and that cause no effect of potentiometer R5.

Used LM741 instead of UA741 that solved fan running on both sides of potentiometer R6.