Motor Fan heat controller


Posted on May 19, 2012

The controller uses one or more ordinary silicon diodes as a sensor, and uses a cheap opamp as the amplifier. I designed this circuit to use 12V computer fans, as these are now very easy to get cheaply. These fans typically draw about 200mA when running, so a small power transistor will be fine as the switch. I used a BD140 (1A, 6.5W), but almost anything you have to hand will work just as well.


Motor Fan heat controller
Click here to download the full size of the above Circuit.

The temperature is set with VR1. Operate the amp until the normal temperature is reached, then adjust VR1 until the fan starts. Then back off very slowly until the fan stops again. Any increase over the normal temperature will start the fan, and promptly




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

Breath-monitor
stun gun schematics
pt05 diy preamplifier
Frequency to voltage converter using LM331
Battery over-discharge protection circuit diagram
555-channel temperature test circuits



Top