My Project about Temperature Controlled Circuit

Good day,

I have read an article about temperature controlled LEDs.
I would like to make one according its circuit diagram.

Look at the diagram,it’s nothing but two LEDs (D1 and D2), whose status are controlled by the temperature of the surroundings. The famous IC LM35 is used as the temperature sensor here. Output of LM35 increases by 10mV per degree rise in temperature. Output of LM35 is connected to the non inverting input of the opamp CA3130. The inverting input of the same opamp can be given with the required reference voltage using POT R2. If the reference voltage is 0.8V, then the voltage at the non inverting input (output of LM35) becomes 0.8V when the temperature is 80 degree Celsius. At this point the output of IC3 goes to positive saturation. This makes the transistor Q1 On and LED D1 glows. Since the base of Q2 is connected to the collector of Q1, Q2 will be switched OFF and LED D2 remains OFF. When the temperature is below 80 degree Celsius the reverse happens. IC1 produces a stable 5V DC working voltage from the available 9V DC supply. If you already have a 5V DC supply then you can use it directly.
The CA3130 datasheet:
However,the difference is I want to use circuit to connect a fan and a heater instead of LEDs,so that I can switch on either fan or heater depending on my set point. Can anyone tell me is it feasible?

Thank you in advance!

Best wishes~


You need to be a member of diydrones to add comments!

Join diydrones

Email me when people reply –


Hiroki Tanaka liked Hiroki Tanaka's profile
Oct 13
Derrick Davies liked lisa TDrones's profile
Sep 23
xemone liked Max Gilson's profile
Aug 31