i would like to create simple circuit to drive an computer fan (12V, 0.5A) is the temperature is above 42 celsius and stop when the temperature decreased below 36 celsius. I am simulating in LTSpice.
The schmitt trigger does trigger when I want. The problem is that the output does not go completely to zero, therefore the pnp transistor never goes fully on and then there is not enough voltage across the "load".
I have read something that this might be due the transistor at the output stage of the opamp. But i really do not now how to fix this problem.
Could someone explain me how to properly drive the load?
n002 = output of opamp n003 = emitter transistor n005 = voltage acros R5