Editing Operational amplifier (section)

==== Output amplifier ====
In the circuit involving Q16 (variously named [[rubber diode]] or ''V''<sub>BE</sub> multiplier), the 4.5&nbsp;kΩ resistor must be conducting about 100&nbsp;μA, with Q16 ''V''<sub>BE</sub> roughly 700&nbsp;mV. Then ''V''<sub>CB</sub> must be about 0.45&nbsp;V and ''V''<sub>CE</sub> at about 1.0&nbsp;V. Because the Q16 collector is driven by a current source and the Q16 emitter drives into the Q19 collector current sink, the Q16 transistor establishes a voltage difference between the Q14 base and the Q20 base of ~1&nbsp;V, regardless of the common-mode voltage of Q14/Q20 bases. The standing current in Q14/Q20 will be a factor [[diode modelling|exp(100&nbsp;mV&nbsp;mm/ ''V''<sub>T</sub>) ≈ 36]] smaller than the 1&nbsp;mA quiescent current in the class A portion of the op amp. This (small) standing current in the output transistors establishes the output stage in class AB operation and reduces the [[crossover distortion]] of this stage.