DC Amplifier Misalignment in Computing Systems

The equivalent input circuit representation for dc misalignment (offset) has appeared in the literature for the special case of a vacuum tube voltage amplifier with infinite input impedance. This paper will generalize the concept of the equivalent input circuit representation for dc offset for the four amplifier types with finite input impedances, and will give the conditions under which the use of each equivalent circuit is justified. In each case, two offset generators which are characteristic of the amplifier alone¿independent of driving source impedance and load impedance termination¿ are defined. Because of this independence, the offset generators are referred to herein as ``characteristic misalignment generators.´´ When the amplifier is connected into a system, a knowledge of these generators permits calculation of the effect of amplifier offset on system performance.