Is Q2 in Figure 11 3 and 4 reversed? Q2 current direction is 3-4 pins, right?thanks
Both emitters (pin 3) are connected to the negative power supply. The collector of Q1 is connected to the positive supply through R2. The collector of Q2 is connected to the amplifier summing junction which will be at a virtual ground. In both cases positive current flow is from collector to emitter (Pin 4 to Pin3).