Automatic Cooling System.

In this project we are making an automatic cooling system in which the fan is activated when thetemperature is increased and the fan is deactivated when thetemperature is decreased. Fan speed is proportional to temperature. This is a very simple and exciting approach towards the thermistor based technology. In this process we can operate a small dc motor directly. The extension of the project is to further add a relay and a relay driver circuit and this will support a table fan or a ceiling fan whatever you choose. But if we use a relay fan speed will not be proportional to temperature. So, in this context our focus will be to get a proportional fan speed without using any relay. Here we will use some simple and easily available components to construct the circuit.