PCB AMIT NIKAM ASHI NAGARIYA CONTENTS What is
“PCB” -AMIT NIKAM -ASHI NAGARIYA
Ø Ø Ø Ø CONTENTS What is a PCB? Materials of a PCB Parts of a PCB 1. Components 2. Pads 3. Traces 4. Layers 5. Jumper 6. Solder Mask 7. Silk screen Multilayer PCB Advantages Disadvantages Uses References
What is a PCB? • Printed Circuit Board • Electronic Board that connects circuit components • PCB is populated with electronic components • PCBs are rugged, inexpensive, and can be highly reliable • Mass manufacturing
MATERIALS OF PCB • Conducting layers are typically made of thin copper foil. • The board is typically coated with a solder mask that is green in color. Other colors that are normally available are blue and red. • Unwanted copper is removed from the substrate after etching leaving only the desired copper traces or pathways
PARTS OF A PCB • • Components Pads Traces Layers Jumper Solder Mask Silk screen
COMPONENTS • Components are the actual devices used in the circuit. • This includes input/output connections. • I/O ports, including power supply connections, are also important in the PCB design.
PADS • Location that components connect to. • You will solder components to the pads on the PCB. • Pads will connect to traces. • Pads have an inner diameter and outer diameter.
TRACES • Traces connect pads together. • Traces are essentially the wiring of the PCB. • Equivalent to wire for conducting signals • High current traces should be wide • Signal traces usually narrower than power or ground traces.
LAYERS • Two layers- TOP and BOTTOM • Most of the components reside on the top layer • Fewer traces on the top layer • Components are soldered to the pads on the top layer of PCB • Higher circuit densities • Most soldering done on bottom layer
JUMPERS • Often, many signal wires need to exist in too small of a space and must overlap. • Running traces on different PCB layers is an option. • Multilayer PCBs are often expensive. • Solution: use jumpers
SOLDER MASK • Protect copper traces on outer layers from corrosion • Areas that shouldn't be soldered may be covered with polymer resist solder mask coating • Designed to keep solder only in certain areas • Prevents solder form binding between conductors and thereby creating short circuits
SILK SCREEN • Printing on the solder mask to designate component locations • Readable information about component part numbers and placement. • Helpful in assembling, testing and servicing the circuit board
MULTILAYER PCBS • More then a top and bottom layer. • Typically there will be a power plane, ground plane, top layer, and bottom layer. • Sometimes signal layers are added as needed.
ADVANTAGES • • • Small Compact Contained in a convenient, rugged board The circuit board fabrication cost (pcb cost) is lower with mass quantity production. Electronic circuit characteristics are maintained with a proper circuit board design. Component wiring and assembly can be mechanized in a circuit board manufacturing facility. PCB’s offer uniformity of electrical characteristics from assembly to assembly. The location of electronic parts is fixed and so it simplifies components identification and maintenance of equipment. Inspection time is reduced because printed circuitry eliminates the probability of error. Chances of wrongly wiring or short-circuited wiring are minimized.
DISADVANTAGES • Re designing is required for the new type of circuit operation. • Very hard to get repaired if it gets damaged. • We can not update it , once printed. • Etching of this PCB generates chemicals which are the harmful for the environment. . .
USES Industrial PCB Manufacturing • Some examples of PCBs that Tabtronics has manufactured for industrial use include: • Controls for ultrasonic technologies • Flex circuits with piezoelectric transducers • Field controls for water treatment systems • Process thickness measurement control
Medical PCB Manufacturing • Some examples of PCBs that Tabtronics has manufactured for medical use include: • Dosimeter product assembly • 2 -axis body movement tracking device used by doctors and researchers • Eye measurement product with remote transmitter and receiver • Hospital inventory control devices
REFERENCES • www. pcbexpress. com • A Practical Guide to high-speed printed circuit board layout
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