ABSTRACT
In the section of this book dealing with input stages I have gone to some lengths to demonstrate that a plain unassisted amplifi er – if designed with care – can provide DC offset voltages at an output that is are low enough for most practical purposes, without needing either an offsetnulling preset or a DC servo system. For example, the Trimodal amplifi er can be expected not to exceed 15 mV at the output. However, there may be premium applications where this is not good enough. In this case the choice is between manual adjustment and DC servo technology. As precision op-amps have got cheaper, the use of DC servos has increased.
