INDEX

COMPARATOR(LM324)
Comparator is a digital IC. The difference between the analog IC and digital IC is that in digital IC the output has only two states, while in analog IC it has more than two states. IC7404, it has two states LOGIC HIGH and LOGIC LOW,IC555 is also digital IC. IC741 is an analog IC because it has output voltage vary from -12v to 12V. Comparator has only two states +vcc or -vcc But LM324 we normally apply Vcc=5V and -vcc=0. So output will have only 5V and 0V. But LM324 output LOGIC HIGH will be aroundVcc-1.5V and LOGIC LOW around .2V. So if you use Vcc=5V then LOGIC
HIGH=3.5V and LOGIC LOW=0V. But LOGIC HIGH for a digital circuit is a voltage greater than 2.4V and LOGIC LOW is less than .8V

Above figure shows the general circuit diagram of a general comparator. If V1>V2 then Vout=+Vcc and if V1<V2 then Vout=-Vcc. Suppose if V1=V2, then output will be +vcc or -vcc theoretically. But practically no such condition exist, because an operational amplifier has a gain of 10^6, so there is no condition exist.