LM709 is a general purpose op-amp. It’s widely used in many applications and it’s internal schematic is available in its datasheet. So I thought… why not build one myself… Using SMD transistors and resistors ofc. You can check out all of the altium deisgner files (schematic and PCB) on my github repo. On this page I plan to post the results of the tests we’re gonna do and compare this discrete version with the LM709 IC in a number of different configurations.