文档介绍：Source: ELECTRONICS TECHNOLOGY HANDBOOK
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PASSIVE ELECTRONIC
COMPONENTS
CONTENTS AT A GLANCE
Overview Filters
Fixed Resistors Passive Filters
Variable Resistors Power Supply Filters
Capacitors Surface Acoustic Wave (SAW) Filters
Inductors Crystal Frequency Standards
Transformers
Overview
A passive ponent is a circuit part that functions without an external power
requirement. The mon ponents are resistors, capacitors, and inductors.
Most of them have two leads. An axial-ponent, as shown in Fig. 1-1, has leads
projecting from each end of ponent body aligned with the long axis of the part, while
a radial-ponent, as shown in Fig. 1-2, has parallel leads projecting at right angles
from its body. Axial leads must first be bent 90° to insert them into the holes of circuit
boards, while radial leads can typically be inserted directly into those holes without bending.
However, both axial- and radial-leaded parts can be inserted by automatic machines.
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PASSIVE PONENTS
2 PASSIVE PONENTS
(a)
Figure 1-1 Axial-ponents: (a) resistor,
(b) and (b) electrolytic capacitor.
Figure 1-2 Radial-leaded capacitors:
(a) monolithic ceramic, (b) solid tanta-
lum, (c) aluminum electrolytic, and
(a) (b) (c) (d) (d) ceramic disk.
The ongoing trend toward more surface mounting of ponents has led to the
introduction of more active and passive “leadless” components that can be soldered directly
to tinned or plated pads on “hole-less” or surface-mount technology (SMT) circuit boards.
Passive ponents such as capacitors and resistors are leadless rectangular chips or
cylinders with metallized end surfaces that are reflow soldered to the circuit boards, but
many ponents, such as transistors and integrated circuits, are in cases with bent
stub or “g