lm339 comparator not working

[ibnul7]

Hey guys, I am trying to use a lm339 comparator and for some reason the output never goes high. Is it even supposed to go to full +Vdd? My Vdd is at 9v but my output goes to 0.34 volts when the noninverting input is greater than the inverting.

Thanks

 

[mvs sarma]

Did you observe that its output is open collector type. See the diagram below .

have a collector resistance and connect to Vcc and the output can be measurable at output pin thereafter.

 

[andre_luis]

You need to put a pull-up resistor at output.


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