Overview

One ought, every day at least, to hear a little song, read a good poem, see a fine picture, and, if it were possible, to speak a few reasonable words.

Johannes Wolfgang Goethe (1749 1832)

In this part, a number of the more common basic circuit devices are discussed. There are of course many types of component and many variants of each, but we will be concerned with general matters rather than the detailed specifics of a particular device. In particular it is worth being aware of the limitations of real devices as these can significantly affect the performance of your circuit. As our present interests are very much involved with SPICE, some attention will be given to the parameters of the models available for simulation. Even for such apparently simple devices as resistors, capacitors and inductors there are many parasitic effects which in one way or another may affect their operation. Parasitic capacity; temperature coefficients; self-resonance; skin effect; permittivity and permeability changes with voltage, current or temperature; and others make the task of reliable design more difficult.

Again it should be emphasized that we are not doing a survey of anything like all the different types of component or even examining those that are discussed in great detail. We cover basic ideas and operation, record some of the less evident matters that should be taken into account and introduce the models that have been developed to allow simulation with reasonable accuracy. The variability of (particularly active) components means that...