What is a comparator and how to use it in IR sensor for a Line or Path follower Robot - IC LM358 & LM324

Comparator

Comparator is a device which compares two input voltages and gives output high/low. In circuit diagram it is normally represented by a triangle having- Inverting (negative) Input (-),Non Inverting (positive) Input(+), Vcc, Ground, Output.

Use of comparator in IR sensor

As above we see that two inputs are required for comparator. One input is from photo-receiver (like photo-diode), other is generated by us using potentiometer. The second voltage is also called as reference voltage for that sensor.

LM358

The LM358 is a great, easy-to-use dual-channel opamp. LM358 applications include transducer amplifiers, DC gain blocks and all the conventional opamp circuits.

                                                   Figure: Pin diagram of LM358