Project : 230VAC Temperature Fan Control

Thread Starter


Joined Nov 14, 2008
I enclose below my version PCB circuit shown here:
It is a circuit that controls the fan speed according to the temperature. The circuit is powered at 230V and uses a thyristor as shown in electric diagram I reproduced it and I attached it below.

Regarding the operation of the circuit, depending on the fan used, switched depending on the temperature is fast enough but if this does not bother the application they are going to use it, then we can say it's a scheme variable 230VAC is very useful.
I used 17W fan - this type:

I studied the possibility to connect an RC snubber between terminals AK thyristor but not required in the application studied and made ​​practical. Or in other words, everyone has the choice.
I attached some pictures below.


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wahab ayad

Joined Jul 20, 2014
hi senoir
in the picutre attatched i observed the knop in controller so is it temp set point and if it how can read the temp setpoint?

Thread Starter


Joined Nov 14, 2008
I don't think you understand the correct operation of the schematic.
Potentiometer P1 sets the reference temperature above which the fan starts working. Also, if you turn the cursor P1, you can turn on the fan and at ambient temperature. So, there is a wide range of temperature values ​​(which can be the reference) that may allow fan operation.


Joined Jul 27, 2014
Looks good mate. Be good if you could step us through the circuit on how it works though.
Makes it easier if the original designer explains it in steps. So basically decompose the schematic down into sections / building blocks with explanation.

Thanks buddy.