I have 2 values of dc signals (less than 1.8V and greater than 2.3V ) coming through a line. I wanted to make 5v when I receive "greater than 2.3V" and make 0V when I receive "less than 2.3V". I thought about using an LM324 as a comparator .(The schematic given in the data sheet is attached). But it doesn't work. Could somebody help me please?

Attached Files

LM324_comparator_testcircuits.pdf (22.6 KB, 61 views)

 

hi,
When you say it dosnt work, in what way dosnt it work.?

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Eric
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If the LM324 and the voltage-setting pot have a supply voltage of 6.0V and the output has a load that doesn't draw more than 2mA then the output high voltage is about +4.8V.

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Uncle $crooge

 

Thanks It worked. I connected a 3.6Mohm between the earth and the Input(pin 3 and 11). But I don't know the reason.It accidentally worked.(When I connected a voltage meter between the input and earth to check the input voltage it worked as I expected. But when I removed the meter it failed. So I replaced V meter with a high resistance ) ??? Just leave this. Thanks again.

 

hi,
Did you try to test it initially without POT2 being connected.?

If POT2 was in circuit the 3.6Mhm: should not have any effect.?

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Eric
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Use the LM339 or LM311 as a comparator rather than the LM324 which is a low-power low-speed op-amp not a comparator.

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