LM324. Because the LM324 is a four-op amplifier integrated circuit, it uses a 14-pin dual-in-line plastic package. There are four operational amplifiers inside, with phase compensation circuits. The circuit power consumption is very small, the lm324 operating voltage range is wide, can be used positive power supply 3 ~ 30V, or positive and negative dual power supply ± 1.5V ~ ±15V work. Its input voltage can be as low as the ground potential, while the output voltage range is O ~ Vcc. Its interior contains four groups of exactly the same form of operational amplifiers, in addition to the power sharing, the four groups of operational amplifiers are separate from each other.