hai, i made a sensor circuit for line follower using lm324 comparator,i have a lot question about it,plz expalin it, i attached diagram of comparartor circuit, i want a maximum output (4to 4.5),pin 3 i put high resistance,the output is 3.7 without turn on the led(D1), D2 is LDR, if i turn on D1 the comparator output doesnot chang(only vary 3.7 to 3.6), what is the working condition of ldr in this circuit? otherwise plz explain the working condition of this circuit.plz