Temperature Control circuit by opamps and lm35(HEATING-COOLING)

Thread Starter

aviotor1

Joined Dec 12, 2016
19
Hello everybody,
I am new here;if i make any mistake forgive me :)

Is that possile to make circuit that controld temerature by fully analog? I mean i just learning the op-amps and they have comparator properties.I just thought that is that possible to if temperature below from any value(no matter what is it) ;System will heat it by stone resistor or something like that.(stone resistor cheap and i have thats why i said it).Otherwise (i mean if higher than that value) ;system will cooling it by any motors or fan.

I have Lm358 opamps(couple of) and LM35 temperature sensor.I have both motor and fan. If possible to create such kind of system i have mentioned above, Could you pls help me to make it happen? thanks.

I don't have a lot of components. I have resistors,Dc supply, some transistors(maybe usefull for fan drive???) and LM358 opamps and lm35 temperature sensor etc...

I would be appreciate if any help... thanksss
 

schmitt trigger

Joined Jul 12, 2010
469
Yes, with an analog temp sensor and a pair of comparators you can do exactly as you require.

The LM358 will not drive directly a motor or fan. But it can drive either a Mosfet (for DC motors) or a Triac optocoupler (for AC line powered motors).
 

MaxHeadRoom

Joined Jul 18, 2013
23,782
What is the heating-cooling components consist of, now it is often done digitally with an analogue sensor and PID control with burst firing control using zero cross over SSR etc.
Max.
 

Thread Starter

aviotor1

Joined Dec 12, 2016
19
What is the heating-cooling components consist of, now it is often done digitally with an analogue sensor and PID control with burst firing control using zero cross over SSR etc.
Max.
Its required to make it by op-amps and transistor.
If i had a chance to choose anyway i would already picked arduino :) But as i said above; its a kind of homework and they want us to make it by opamps.
 

Reloadron

Joined Jan 15, 2015
6,121
This is a good place to start learning comparator circuits, as in we could compare the temperature we have to the temperature we want and fashion a very basic On / Off temperature control scheme. The comparator could maybe drive a transistor which would turn maybe a relay or contactor on and off which would allow a heater to turn on and off as heat was needed or called for. You have a sensor and you have a comparator, life is good.

Ron
 
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