Window Comparator Has Strange Outputs

[Scr1bbl3]

Hi all,
I found the circuit below in the interweb and deiced to build it for giggles. I am using a dual BA4560 ic with the voltage divider resistors 10K each at 5VCC. The pull-up resistor is 5.1K. The trip points should be 1.66V and 3.33V
The outputs below 1.66 and 3.33 read 3V, not zero. Between 1.66 and 3.33, I do measure 5V. Any ideas why the circuit doesn't go to zero?
Thanks,
Scrib

[ataradov]

BA4560 is an opamp, not a comparator. And it actively drives the output (push/pull), while your circuit is designed for an open collector output.

You get outputs of the opamps fighting each other. One tries to drive VCC one tries to drive GND, you get the middle voltage.

While it is possible to use opamps as comparators in some cases, it is not going to work here.

[gnif]

Double posting is not permitted on these forums, please refrain from doing it again:

https://www.eevblog.com/forum/beginners/window-comparator-has-strange-outputs/msg4837664/

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