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Fan regulator

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I want to vary the speed of fan according to ambient temperature in the room.As temp. increases fan speed should also increase & viceversa..
No uC & uP......:confused:
The circuit should be designed to save the power consumption...


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Yep. First thing you have to do is to find an temperature censor. You need to know the temp/voltage caracteristic of it.

Then you should make an hysterese circuit. It's often a simple opamp circuit containing 4 resistors (two deciding hysterese level and one voltage divider).

Well, not true, you probably need one more opamp as voltage follower to the voltage divider. Those two resistors could be replaced by a potmeter.

And you need to investigate how to calculate the resistors to the hysteresis circuit (I don't remember it right now)

The circuit should be designed to save the power consumption...
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this is ceiling fan operated on 230V.
Yes, but the circuit I provided is seperate. It will take the temperature sensor and detect what temperature the fan is dissipating. So you can still have the fan connected to 230V but the seperate fan controller (using the temperature sensor) will be powered by 12V.


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A fan doesn't cool a room. A fan cools a sweating person.
Maybe if the room has no insulation and its windows are in the sun all day then maybe a fan will cool it.


Well-Known Member
Fans actually make a room hotter because the hot air will naturally try to stay up near the ceiling and the cooler air down by you. use a fan to swirl it up and the temp down by you rises.
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