Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [pcb]

PCB is the acronym to Printed Circuit Board. A PCB is a carrier for the circuit's components and their electrical connections.

Most are made from a version of fiberglass and epoxy resin called FR-4. These boards are usually green, but can be any color. PCBs are typical 63 mils (1.6 mm) thick (1 mil = 1/1000"). Other thicknesses used are 39 mils (1 mm) and 31 mils (0.8 mm). PCBs can be single layer (traces on one side), two layers (traces on both sides), or multilayer (traces (or planes) on both sides and internal layers).

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Decoupling caps, PCB layout

I guess I've been somewhat ignorant when it comes to the finer details of pcb layout. Lately I've read a couple of books that try their best to lead me on the straight and narrow. Here is a couple of examples of a recent board of mine, and I have…
morten
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Are solder fumes bad for me?

I do a fair bit of soldering (lead-free). Is breathing in solder/flux/paste fumes actually going to harm me? Are cheap fume extractors worth buying?
Toby Jaffey
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Best One-Off DIY PCB Creation Technique

I have finally built up a lab to design electronics in. I have quite a few designs I would like to test. I have tried the printer toner/iron technique a few times but have found that I cannot create small pitch sizes as they tear off while removing…
ThaKidd KG5ORD
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Looking for circuit board material that can be dissolved

We are working on a product where the entire device needs to be dissolved in liquid after the device has operated and the device is no longer usable or desired. This is a down-hole application. The device body is either aluminum or magnesium. …
Dwayne Reid
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Why is there such a strong preference for 45 degree angles in PCB routing?

I've always wondered this: every single modern PCB is routed at 45 degree angle increments. Why does the industry prefer this so much? Doesn't any-angle routing offer more flexibility? One plausible theory would be that the existing tools only…
Roman Starkov
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Why are circuitboards traditionally green?

Green is the most common circuit-board color because it has become an industry standard. What I'm interested in is How the traditional "PCB Green" become a standard in the first place? Were there any interesting historical reasons for the initial…
Connor Wolf
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How to connect USB Connector shield?

How should I route USB Connector shield on PCB? Should it be connected to GND plane right where USB is placed, or should the shield be isolated from GND, or should it be connected to ground through ESD protection chip, high resistance resistor or…
Andrzej H
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What is Copper Thieving and why use it?

On many boards I've seen, there are little copper dots used for the purpose of "Copper Thieving". They're small round copper dots connected to nothing and arranged in an array. Supposedly they're for balancing the copper on the boards to improve…
Gustavo Litovsky
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What kind of glue should I use for PCB-mounted components to avoid vibrations?

I want to protect the PCB-mounted components from vibrations. What kind of glue/substance should I use? What are the most prone to failure components due to vibrations?
m.Alin
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What do the PCB markings mean?

On a printed circuit board, I see lots of tiny letters and numbers. Is there some kind of standard that dictates what letter indicates what type of component?
kinokijuf
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How do you cut PCB?

I just spent about 20 minutes trying to cut through a PCB with a hacksaw. These things are really tough. What is the correct tool to cut PCB material, and get a nice straight line? I saw something about a guillotine, but can't find a vendor.
littlebirdceo
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How do I identify SMD components? (or how do I identify any component)

How do I identify the markings on an SMT component and match it up with a part number so I can be a good designer and actually look at a datasheet (and read the whole thing)? Or identify a part to replace an unknown part on a PCB?
Voltage Spike
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Why are there teardrops on PCB pads?

What's the use of the teardrop shapes around some PCB pads?
Federico Russo
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How can PCB trace have 50 ohm impedance regardless of length and signal frequency?

Hmm, this seems to be just another question on line impedances. I understand that when we say "transmission line" effects we talk about things like cross talk, reflections and ringing (I guess that is just about it). These effects are not present at…
quantum231
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What is the usage of Zero Ohm & MiliOhm Resistor?

I am new to PCB design and I noticed that some schematics use 0Ω or 100mΩ resistors. What is their purpose and why do we need to use them in our PCB design? Normally if we wish to probe how much current the load is taking, we put a jumper pin across…
Dennis
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