I am looking for PCB layout of temperature controlled fan using thermistor and IC 741. Can anyone help, please?

Description Th1, the 50K thermistor, is a standard type. Mine was a bar or rectangular aspect. Available on Tandy / Radio-Shack. Almost any guy will. I have experimented with different models from 22K to 100K and everything worked well after replacing the trimmer pot. The one used in the above circuit diagram was a 50K model. This 50K was measured accurately at 25 ° C and with a tolerance of 10%. The resistance increases as the surrounding temperature decreases. The tolerance for my application (cooling of a large coolrib power supply) is 10%. Another name for this thing is 'NTC'. NTC stands for "Negative Temperature Coefficient", which means that when the ambient temperature decreases, the resistance of this thermistor will increase. I have replaced my thermistor with a 60K hermetically
Sealed since the environment for my application may contain corrosive particles that may affect performance at a future date. P1 is a regular Bourns trimmer and adjusts a wide temperature range for this circuit.
I used the 10-turn type for finer bit setting but the regular type will work for your use. R1 is a "safety" resistor in case the potentiometer P1 of the set capacitor is set all the way to '0' ohms. At that time the thermistor would get the full 12 volts and it will get so hot it will put blisters on the fingers ... :-) R3 feeds some hysteresis back into the op-amp to eliminate the 'chatter' relay when the temperature The thermistor reaches its threshold point. Depending on your application and the type you use for Q1 and Re1, start with 330K or less and adjust its value down until you are satisfied. The 150K value shown in the diagram worked for me. Decreasing the value of R2 means more hysteresis, just do not use more than necessary. Or temporarily use a trimmer pot and read the value. 120K worked for me.

Transistor Q1 can be a 2N2222 (A), 2N3904, NTE123A, ECG123A, etc. It is not critical at all. It acts only as a switch for the relay so that almost any type will work, as long as it can provide the current needed to activate the relay coil. D1, 1N4148, acts as a spark arrester when relay contacts are opened and eliminates false tripping. For my application the 1N4148 was pretty good since the tiny relay I used was only 1 amp.
However, you can use a variety of diodes here, my next choice would be a regular purpose 1N4001 or something like that and should be used if your relay type can handle more than 1 amp. If you like to make your own pcb, try the one above. The PCB is equipped with holes for the relay, but may not suit your particular relay. It was designed for an Aromat type HB1-DC12V.

The variety and model of the relays is very large. How to ride then? Well, I left a large space on the PCB to mount your relay. You can even mount it from the top down and connect the cables individually. Use silicon glue, cyanoacrylate ester (crazy glue) or double sided tape to hold the relay in place. It works well. Note that the PCB and the design do not agree with the circuit diagram with regard to the connection of the fans. The PCB measures approximately 1.5 x 3 inches (4.8 x 7.6 mm). If you print the PCB to an inkjet printer it is likely not to scale.