PCB_MF

6.Polyimide Laminate one of the most heat res Reinforced with woven g find use in demanding mapplications and in special m retain higher copper bontemperatures than the genematerials. -----------------*****--------

es:sistant polymers.glass fabricmilitary and aerospace multi layer circuits.nd strength at soldering eral purpose Epoxy -----*****--------------

UNILAYOUT GENERAL R

IT 3RULES AND PARAMETERS

3.1 LAYOUT DEFINITIOLayout design is the sketccomponents and copper coare interconnected the respthe specified area of PCB.

ON:ch of outline ofonductor routings, whichpective components within

3.2 History and BasiIn USA, PCB is call it as “PWB”Wiring Board”. PCB is invented by Mr.Paul Ei

ic’s of PCB’s:” expansion of PWB is “Printedisler in 1937.

Definition of PCB :The PCB or PWB providedstructure for mounting & hocomponents as well as the ebetween components.A PCB consists of non-con(typically fiber glass with epconductive pattern or circui

d both the physicalolding electronicselectrical inter connectionnducting substratepoxy resin) upon which aitry is formed.

TOP LEVEL METAL OF THE PC Copper is the most prevaNickel, silver, tin, tin leads and gresists or top level metal.

CB:alent conductor, although, gold may also used as etch

3.3 TYPES OF PCB:•Single sided PCB•Double sided PCB•Multi layer PCB



Single sided PCB have a condu Double sided PCB’s have a cofaces Multi layer boards consists ofinsulting material bonded toget

uctive patterns on one side.onductive patterns on both f alternating layer of conductorther.

3.4 Single sided PCB layourequirements1) Are edge connecto2) Are solder termina3) What are the curre requirements?

ut designors required?als required?ent & voltage

All components must be repres

sented pictorially

•There can be no cross over

r.

 Keep point to point conductorshort as possible. When unable tfor conductor runs use 45o bends

runs or straight asto use straight liness

•Polarity marks on the layodrawn for power terminal, dpolarized capacitor

out should be diodes,

•Place all resistors’ dioparallel with each othe

odes etc.er.

•Mount resistors capacitors & dtogether as possible, but enougbe allowed between componenremoved

diode as closegh space shouldnts for their servicing &

The space between conductor ppeak voltage potential across c

paths depends oncircuit Components.

•Multi axis component placemaccepted.

ment is not

•If the layout consistsall IC’s parallel to eachat or near the centre o

mainly of IC’s placeh other & group themof the PCB.

•Place or group the tran& columns

nsistors & SCR’s in rows

•Reduce the use of Jumpers

to minimum.

3.5 Reference Designato A Assembly AT Attenuator isolator B Fan, Motor BT Battery C Capacitor CP Coupler CR Diode, Thyristor DC Directional coupler DL Delay line Ammuncator, Signaling d DS (Audible or visual) Lamp E Miscellaneous Electrical

ors Power Supply Transistor, SCR PS Resistor Q Thermistor R Switch RT Transformer S Terminal Board T Thermo Couple TB Test Point TC TP Intigrated micro CKT device Electron Tube : LED U Part V

F Fuse VFL Filter WG Generator X

VR Voltage RegulatorW Cable transmissionX Socket

H Hardware YJ Electrical Connector (Starionary Z Portion) jack GHY Circular SK RelayL Coil, InductorLS MeterMG Motor-GeneratorMK MicrophoneMP Miscellaneous Mech. partsP Electrical Connector (Movable portion) plug

Y Crystal Unit (Pize Electric or Quarter)Z Tuned circuitGround EarthSymbols Common Chassis

3.6 Conductor Routin

ng Practices

3.7 General Rules For PCB D

Design