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Q42. When you are using an ohmmeter to test a transistor for leakage, what is indicated by a low, but
not shorted, reverse resistance reading?
MICROELECTRONICS
Up to now the various semiconductors, resistors, capacitors, etc., in our discussions have been
considered as separately packaged components, called DISCRETE COMPONENTS. In this section we
will introduce some of the more complex devices that contain complete circuits packaged as a single
component. These devices are referred to as INTEGRATED CIRCUITS and the broad term used to
describe the use of these devices to miniaturize electronic equipment is called MICROELECTRONICS.
With the advent of the transistor and the demand by the military for smaller equipment, design
engineers set out to miniaturize electronic equipment. In the beginning, their efforts were frustrated
because most of the other components in a circuit such as resistors, capacitors, and coils were larger than
the transistor. Soon these other circuit components were miniaturized, thereby pushing ahead the
development of smaller electronic equipment. Along with miniature resistors, capacitors, and other circuit
elements, the production of components that were actually smaller than the space required for the
interconnecting wiring and cabling became possible. The next step in the research process was to
eliminate these bulky wiring components. This was accomplished with the PRINTED CIRCUIT BOARD
(PCB).
A printed circuit board is a flat insulating surface upon which printed wiring and miniaturized
components are connected in a predetermined design, and attached to a common base. Figure 2-20 (view
A and view B) shows a typical printed circuit board. Notice that various components are connected to the
board and the printed wiring is on the reverse side. With this technique, all interconnecting wiring in a
piece of equipment, except for the highest power leads and cabling, is reduced to lines of conducting
material (copper, silver, gold, etc.) deposited directly on the surface of an insulating "circuit board." Since
printed circuit boards are readily adapted as plug-in units, the elimination of terminal boards, fittings and
tie points, not to mention wires, results in a substantial reduction in the overall size of electronic
equipment.
