Comparator problem.

Welcome all. In circuit I currently work on I need to create threshold detection. I have signal that I compare to preset value of about 2V (2V to sample against steeper slope). I am currently using LT032. Picture “lt032_threshold_comparator_1” shows result of it. However, since I want to connect output of comparator to Arduino, I can not have negative value. What would be best solution in order to still use LT032? I tried connecting LT032 op-amp to positive supply and GND only. However, results of it are far from desirable. Picture “comparator 2-2” shows result of single rail supply to op-amp. As much as it behaves in similar way however ti has output permanently high when + input signals is equal to zero. Is there any way I could achieve it without any extra components?

You could just feed the output of the comparator through a diode and then a voltage divider to give a 0 or 5v signal to the Arduino.

Thank you Sir it workes perfectly!

If you’re just cleaning up what is a digital signal with poor rise and fall times, you can avoid the extra components of a comparator by using a simple Schmitt trigger input logic gate.

The 74HC14 has been used forever for this application, single gate chips are available in the SOT-353 and even smaller BGA packages these days. Example: 74LVC1G14SE-7

What arduino do you have? Uno, mega, nano etc has an embedded comparator.

Hi, See [Popular-ICs - ArduinoInfo](https://arduinoinfo.mywikis.net/wiki/Popular-
ICs#LM393_2x_comparator)

This is a nice 5V single supply comparator. Some circuits / info on that page also...

OP's pictures:

  1. The device used is TL032 (the same typo as in your previous post).
  2. Op amps are not comparators. While they may be used for this task they are not designed for this purpose and will give poor results (such as slow response time).
  3. Arduino Uno has already a comparator built in. Probably you don't need any extra part for this task.

Yes, don't get into the bad habit of using opamps as comparators, some have back-to-back diodes across
the inputs, most are really slow to recover from saturation, and some just fry if you do it. Just note
that most comparators have open-collector logic outputs.