Lanes of copper on a printed circuit board, for carrying current or signals between pads

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1answer
87 views

Why are these Vias of Different Shapes

While looking at how other circuits bring AC mains into their circuits, I came across this design where there are 3 differently shaped vias (from top to bottom): Figure of ...
6
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2answers
307 views

How to connect large traces to pads in PCB?

I am designing a PCB, and 10 A-15 A current is flowing in a trace. I think a 300 thou track should be used for 1 oz Cu-thickness. I see that it is impossible to connect two pads ...
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2answers
69 views

Pseudo RF in embedded boards

I noticed that wifi-capable embedded boards integrate the RF into the board design instead of having a separate, add-on wifi card. They have meshes that are etched into the board and the rest of the ...
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1answer
61 views

What is the impact high current through of narrow trace?

A 20mil external trace with a copper weight of 0.5oz can carry ~2.5A with a temp rise of 30C (according to Saturn PCB Toolkit) If my signal was a digital signal < 10khz with rise/fall time in the ...
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3answers
54 views

High AC voltage affects the pcb

I had a PCB board printed that has some relays that are connected to 220 VAC circuit. Now unfortunately some traces passes near the relays and are affected by this high voltage causing the circuit to ...
0
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0answers
57 views

Maximum length for the trace

I'm struggling over this question: In a microprocessor currents are sent through various materials for communications and power. Assuming you want to deliver a 5𝑉 ± 0.5𝑉 signal through the trace to ...
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1answer
124 views

Formula for voltage drop vs PCB trace width, temperature, current, and trace length

I need to find out the voltage drop in the PCB traces with respect to the possible factors like: copper thickness, trace length, trace width, temperature, etc. I found some calculators available at: ...
2
votes
1answer
120 views

PCB Crosstalk calculators… Center line distance or trace separation

I am still a beginner in this field, and recently I've learned about Crosstalk and Crosstalk calculators. I've tried the one on EEweb, Saturn, Ultracad and some others. Some of these calculators ask ...
0
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1answer
47 views

In Altium Designer, how can you set the autotracer to route all traces with as equal lengths as possible?

Note that this board does not require a power or ground plane, since it's just used to bridge two boards. I want the traces to be as equal in length as possible in order to minimize any difference in ...
4
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3answers
426 views

Can I prevent copper traces from delaminating due to soldering heat?

I'm making a PCB that has a 100pin QFP pacakge microcontroller. After gaining experience with the UV photoresist process and reliably making the small, 0.5mm traces, I have a new problem: the copper ...
0
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2answers
61 views

Why polygon pour size and trace width don't influence each other in altium

Im using some thin traces in certain areas of the board that I want to have beefed up with a polygon pour. However, when I run the rule check it just ignores that the width of the traces is now ...
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3answers
73 views

Good method to remove tenting on vias after assembly for debugging?

This is a question about modifying an assembled board to make it easier to debug. In a perfect world, I would have left the bottoms of these vias un-tented. Whoops. I have two BGA parts on a PCB, ...
8
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3answers
795 views

Can I solder a wire between two leads on a PCB to make up for a trace that isn't wide enough?

I have a PCB that has 2 traces on one corner who's width only supports a ~10a load. I need support for a 20a load. Actually, it really only needs to support a 15amp load but I'm trying to build in ...
2
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2answers
179 views

How does Altium Designer's “impedance constraint” feature work?

Altium has a design rules option for setting a track width constraint according to line's impedance (e.g.; 50\$\Omega\$). How do I use it? Please give me instructions or a link to an online tutorial. ...
0
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1answer
77 views

Trace aligment in a double sided PCB

Are there any layout requirements/special considerations when routing traces on top and bottom layers of a double sided PCB, e.g. angle between traces, can traces pass beneath an IC, etc? I know that ...
2
votes
2answers
202 views

What types of signals should be considered to have a 50 Ω trace impedance?

Generally speaking, what time of signals should be designed to have a 50 Ω trace impedance ? Some datasheets I've read have specifically mentioned 50 Ω but others have not. Is it good practice to ...
3
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1answer
96 views

What does “50 ohm system” mean?

I'm looking to use the following switch to switch an SPI bus ( CLK <= 2Mhz) between two different devices. I'm reading the datasheet to see if the the frequency of the signals are going to be ok, ...
2
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3answers
1k views

What is a suitable temperature rise for PCB traces?

I'm designing a PCB for a 10A relay and am trying to determine what the trace width should be. According to this trace width calculator, the biggest factors in the width are copper thickness, ...
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3answers
165 views

How can I “print” traces on the back of a ceramic package?

I have a project I'm working on that is so tightly packed that I'm totally out of room. I could save the whole thing by slapping a bunch of surface mount LEDs (30 of them) on the back of a ...
6
votes
1answer
381 views

Trace width and clearance calculations

What is the math behind traces and clearance calculations? I am designing a PCB, which will carry 12V and 6A, what should be trace width and trace clearance? Similarly, what should it be for 12V 3A, ...
9
votes
2answers
722 views

Is there any disadvantage to changing trace width in the middle of a trace?

Say I have a trace running across a board. It's 50 mils the majority of its length, but in one short place it narrows to 25 mils to make it through a tight area. As best I can tell, this will be ...
1
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1answer
119 views

Identify and replace a resistor [closed]

My APC UPS stopped working. I have had it for many years and it was serviced once by APC while in warranty and never opened again. Now since it is not in warranty anymore I opened it and saw two ...
0
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1answer
102 views

PCB etching from transparency

I wonder if someone could help me. A few days ago, my brother gave me all of his electronics, seeing that he doesn't need it anymore. I'm keen to learn electronics in depth and have basic knowledge ...
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2answers
272 views

Parasitic inductance of PCB tracks

For a PCB design, the longer the track length the greater the parasitic inductance right? But why would this be a concern if I'm working at low frequencies (e.g 50-60Hz) because it'll behave similar ...
3
votes
1answer
396 views

Are traces exiting a pad at an angle bad?

I have been told in the past that you should always have traces leaving a pad on a straight line. The reason I was given was that it could create an acid trap. From what I have read this is not ...
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4answers
6k views

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 ...
3
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1answer
515 views

Are there any rules of thumb when computing pulse current ratings for PCB traces?

Say I have a surface PCB trace, 4 oz, 50 mils. That trace should be able to carry around 15 amps continuous, according a calculator I'm using. (Obviously your trace ampacity estimates may vary with ...
8
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5answers
646 views

Best way to test a high current pcb design 70A @ 12V

I designed a circuit (MOSFET HBRIDGE) that Should Be able to handle 70A @ 14V. Now that the board is sent out I am on to thinking about how to properly test it. Right now the most logical way I have ...
5
votes
2answers
282 views

What should be considered when sizing trace widths for digital logic signals?

For traces that carry a static DC current, it's pretty easy to calculate the minimum trace width based on the required ampacity of the trace. However, I'm not sure what should be considered when ...
3
votes
1answer
392 views

Power Plane and Decoupling Capacitors Routing

Forgive me for my simplicity. I'm just a hobbyist and not an engineer by trade. I am trying to make my first 4 layer PCB in Eagle and I have a question I cannot find the answer to regarding power ...
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3answers
228 views

11A trace width

Using this PCB Trace Width Calculator the external tace width for 11A (default settings) is suggested as 8.21mm. Is this acceptable? I was expecting something bigger, and just wanted to check that ...
2
votes
2answers
616 views

In Altium how do you increase the trace width from a Pour to GND Vias and Pads?

In my PCB layout I have a ground power connector and several pads where I would like thick traces to connect to the ground plane. When I use the polygon pour feature, it will connect these with 4 ...
5
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1answer
2k views

How to calculate parasitic capacitance in a trace?

I am given the equation for parasitic-capacitance as: \$ C = \dfrac{\epsilon_r \cdot \epsilon_0 \cdot L \cdot W }{ d }\$ I am also told my trace is to be 1000 micrometers long (1mm) and 45nm wide. ...
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3answers
5k views

How to make traces on an universal PCB?

I hope this question won't be closed as too subjective. I'd like to know best practice - how to make traces on universal PCB's with individual holes without traces (like the following image). My idea ...
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1answer
147 views

SDRAM on opposite side of board with respect to uC

Just a quick question. Is it advised against to place a high speed memory device on the opposite side of the PCB with respect to the microcontroller? And if it is ill advised, how is it possible to ...
4
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2answers
630 views

Why Altium routes trace to the side of the pad?

I am curious, are there any reasons why Altium tends to route a trace to the side of a pad, instead of the top? The top looks more logical, since it will not disturb other traces in a SOIC for ...
4
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1answer
341 views

Trace width to 0805 pad?

How worried should I be if I route wider than 10 mil trace to 0805 pad? Would 16, 20 or 24 mil trace cause soldering problems without making 10 mil neck?
5
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2answers
325 views

Satisfactory Margin for Traces from PCB Edge

I've had problems routing too close to the edge of a PCB before and was wondering if there's a suitable rule-of-thumb that I should use (maybe to put in a design rule in Altium somehow with my ...
1
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2answers
531 views

How do you adjust the trace rotation on a Hameg HM 307?

I have a [rather old] Hameg HM 307 oscilloscope with the trace rotation slightly off. There is no trace rotation adjuster anywhere on the outside of the device. The user manual mentions that it is ...
2
votes
3answers
1k views

Repairing broken trace on commercial board

A friend has a USB flash drive on which the SMD USB connector broke off. When it broke, it pulled the pad traces off the board with the solder. We are trying to think of a way to reconnect the ...
3
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3answers
2k views

How to measure propagation velocity through a trace on a pcb?

With a pcb in hand, how to measure the propagation velocity of a path from point A to point B, with accuracy in the picoseconds range?
1
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1answer
201 views

Unoccupied SMD and TH pads and noise/interference/capacitance

Imagine a rather noise sensetive application, My question is if there are unoccopied pads for SMD and through-hole are existing on the board and somehow connected to other components through theire ...
2
votes
2answers
459 views

How to calculate typical signal trace clearance?

Knowing nothing more than most of the signal traces on a project are 7.5mil and it's a high end audio product, i.e. it's not a high frequency or any 'advanced' application, what would be a safe ...
2
votes
3answers
2k views

Eagle Schematic and Board layout design for simple opamp module questions

Hopefully I'm not doing anything illegal, I posted a very similar question a few days ago, but this one is different. Here is what I've been working on the past couple days, trying out different ...
12
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4answers
2k views

When laying out circuit board traces, what impedances do i need to consider?

I do low-speed circuit design for microcontrollers and such (usually <20MHz) and now I'm getting started on some more high-speed circuits. What I want to know is: What considerations need to be ...
4
votes
2answers
513 views

LM13700 Question

I'm currently troubleshooting a state-variable filter I built. All of the filter types work, but the resonance pot has no effect. Tracing a sine signal through the feedback pathway, I found that it ...