# What is inside a General Purpose Operational Amplifier

I am trying to analyze the building blocks of an operational amplifier and for that purpose I have chosen, probably one of the most famous and earliest op-amps built, ua741.

I have figured out most of the building blocks, such as differential pairs, push-pulls, current sources, class AB op amps etc, however there are still some parts that I don't have any explains yet. One of which the highlighted line below for the class AB amp which I was expecting to be connected to Vcc-.

What is the function of the yellow line?

• righto.com/2015/10/inside-ubiquitous-741-op-amp-circuits.html – G36 Jun 9 '17 at 15:45
• Everything you need to know, right here – Mtk59 Jun 9 '17 at 21:44
• Two fantastic, fantastic recommendations, however, if you have noticed already, the path that I have highlighted does not exist on any of the earlier 741 schematics and the path feeds back to the Gain Stage rather than the Differential Amplifier block, going in particular from Q17 to Q22 and not to Q5 in Figure 2: Detailed schematic diagram of the @Micah 's recommendation. :) – Mehrad Jun 12 '17 at 23:37