Please, can you guys help?

Thread Starter


Joined Oct 10, 2014
Hello guys, I'm having some trouble with a electronic project that my professor gave to me.
The objective of the project is to create a circuit to turn on a cooler (fan 80mm).
The especifications are that we need to use a bipolar junction transistor as a temperature sensor, when a warm object ( ex: soldering iron) is approached, the circuit must trigger the cooler. The ideia is to vary the hfe of the transistor to use him in the cut reagion.

I was trying to make this with a relay, and using the BJT saturation region.

Sorry for bad english, isnt my native language.
Hope you guys can help me.


Joined Oct 2, 2009
Firstly, here are some guidelines to posting on forums.

Use a subject title that is more useful than "Please, can you guys help?"
Something like "Temperature controller circuit" would be better.

Show a schematic of what you are attempting to create.

All school assignments should begin by showing your efforts.