The LM324N Single Supply Quad Operational Amplifiers DIP-14 Package. The LM324 series are low−cost, quad operational amplifiers with true differential inputs. They have several distinct advantages over standard operational amplifier types in single supply applications. The quad amplifier can operate at supply voltages as low as 3.0V or as
high as 32V. This is used on many arcade and pinball game PCB and this can also replace the MC3403.