I've seen this circuit from https://www.allaboutcircuits.com/technical-articles/advantages-of-the-actively-loaded-mosfet-differential-pair/
How are the drain voltages equal?? I can't seem to figure it out, it's not even symmetric?
Vd3 = Vsply+ - Vsg = Vsply+ + VGS
I can see that but what about Vd4??It can't be due to symmetry. Q3 forces its drain and gate to be equal with a short, but Q4 doesn't have that.