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I have an LM339 IC from Radioshack that I am hoping to use as a motor driver.

I read many resources on how the L239D can be used as one. I don't have enough circuit experience to truly know the difference between the two and googling shows many wiki pages I couldn't fully understand.

Can the LM339 be used as a motor driver?

I did a quick comparison of the two circuits here LM339 and L239D

But I am still unsure. I don't want to fry my board so I am asking first.

  • I looks as if it's doable. forums.parallax.com/discussion/112585/lm339-h-bridge – Sam Hammamy Sep 19 '16 at 22:00
  • Yes I think its doable too . This is an interesting question it reminds me of all the less obvious applications of the 55 timer. I guess the answer to your question is basically yes you could use it to drive a small motor (uses less than or same as 20ma and less or same as than 1.5v. – qwerty10 Sep 19 '16 at 23:47
  • For example, It would be a variation of a battery comparator circuit with the LED replaced by a small motor with flyback diode, and it would be set to trigger at arduino 5v. Note that directly connecting such a motor to the arduino output pint would damage the Arduino (e.g. it would not output the high current properly once it was damaged with such a small motor). I think it would need more than one LM339 (though maybe its possible with one LM339) arranged in a clever way to protect the arduino and drive the motor.You may also need to add a few cheap parts too for the circuit. – qwerty10 Sep 20 '16 at 0:04
  • @qwerty10 thanks for your answer! It's a lot of trouble. I went ahead and ordered the L239D. I am writing up the code while I wait on delivery. – Sam Hammamy Sep 20 '16 at 1:37
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The LM339 is a comparator, not a motor driver. The L239D is a dual H-bridge motor driver.

They are completely different things. One is used for comparing two voltages (up to 4 times, it's a "quad"), the other is used for driving motors.

The LM339 can output an absolute maximum of 20mA. That's half what the Arduino itself can output on an IO pin!

You could use the LM339 as part of the control circuitry to control a H-bridge, but it cannot itself drive a motor in any way, shape, or form.

  • Not to mention the 16mA drive capability is only for the LOW level. The HIGH level current is rated in nA (which is more likely leakage current). Outputs for the Comparator OP AMPs are typically open-collector and they also needs external pull-up. – KIIV Sep 21 '16 at 8:32

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