Despite the very considerable increase in the use of ICs over the past ten years, passive components are still the mainstay of the electronics industry. The strong emphasis that is given to semiconductors, and ICs in particular, in teaching courses at all levels, however, causes the subject of passive components to be neglected, and many technicians would not know, for example, how to wind a 10 |LIH coil if they did not possess an amateur radio handbook to help them. Many, in fact, would not know how to specify or use such a component, now so much less commonly used. A passive component in this context has been taken to include any component which does not depend on the use of thermionic emission or semiconducting carrier effects, rather than the narrower definition of resistors and capacitors only. The simpler definition, that of no power ampHfication, would rule out components such as relays or cells that can usefully be classed as passive.
