Help with Activating DC Motor when certain Temperature Reached using OP AMP 741 and LM35

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marshallcroz

Joined May 29, 2017
2
Hi Guys, we have a homework that needs to activate DC motor when LM35 reached a certain temperature. I'm struggling to create a schematics since im not really good with electronics. My Idea so far is to use (2 OP AMP Inverting Amplifier to amplify the voltage then compare send the output to another OP Amp Comparator) My problem right now is how it will activate the DC motor? Can someone provide me a simple schematics for this.
 

wayneh

Joined Sep 9, 2010
17,496
A single comparator would do the job. You don't need to amplify the LM35 signal unless you need more precision than about 1C.

A different op-amp or comparator would simplify your circuit but you can do it all with the 741 if you have to.

But, you need a transistor to switch power to the motor. A MOSFET is a good choice.
 
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