I have a question about my project. I'm going to make a temperature-stabilizer. To make this, I think I should use a TEC with a H-bridge and a LM35. First of all, I tried to make a H-bridge by myself, I have only used four NPN transistors and It didn't go well. Then I bought L293D motor driver - not the module one, tried it and it works well. But as datasheet says, it's output current is max 600mA. But this current doesn't make TEC work efficiently. So that, I need to amplify the current. But I don't want to buy high amp motor drivers, hardwares are to expensive in my city. Of course I'll if there's no another way.

Arduino will be used to get temperature values from LM35 and give the H-bridge voltage, control the current direction when necessary. I learned how to use transistors to amplify but if I'll change the direction, it won't work. But I don't know how to make this circuit.

The algorithm that I thought using is this:

Algorithm of Temperature Stabilizer for +-3*C degree

The scheme that I thought using in this:

The scheme that I thought using in this.

What should I do to solve my problem? Thank you for all.


  1. My Tec1-12706 Datasheet: http://www.thermonamic.com/TEC1-12706-English.pdf
  2. LM35 Datasheet - (I have LP package): https://www.ti.com/lit/ds/symlink/lm35.pdf
  3. L293D Datasheet: https://www.ti.com/lit/ds/symlink/l293.pdf
  4. The transistor method to amplify: https://www.youtube.com/watch?v=WZD9RZoMhVE
  • Amplifying the current is basically what the LM293D is doing. You need a more powerful H-bridge. There's not really any way around that.
    – Majenko
    Mar 24, 2020 at 15:07
  • Use LM298 which provide up to 2A.
    – hcheung
    Mar 24, 2020 at 23:49

1 Answer 1


I am interested on this as I have the same issue. What about using a FET or MOSFET to amplify the current that the LM293D provides?

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