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

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Unidentified Component and RefDes EC

Hello Everyone, I am trying to identify components with RefDes EC1 and EC2 in this circuit (the boxes at the top with markings 100-10Z). I have done a lot of searching and EC is not even an ...
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0answers
43 views

Problems with Infrared circuit on a PCB - Is it the board or schematic?

I am using the toner transfer method to apply my circuit for 6 sets of infrared emitters and collectors connected to an RJ15 cable on a PCB for use with a Raspberry Pi B+ board (connected via IDE ...
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1answer
85 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 ...
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839 views

'bridges' on a PCB copper layer

I've come across a design where each pad was connected using 4 'bridges' to the GND copper layar. What stands behind these 'bridges'? Why not make a full copper layer with only solder-mask defining ...
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2answers
65 views

Why the \$F_{knee} = 0.5 / T_{r}\$?

In "High-speed Digital Design - A handbook of black magic" p. 2, The knee frequency for any digital signal is related to the rise (and fall) time of its digital edges, but not to its clock rate: ...
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36 views

Altium can't output NC drills file?

I'm about to send my gerber files to OSH park however I'm having trouble generating the drill file in Altium 14.3. The output file is some other format than the Excellon / NC Drills file that the fab ...
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1answer
44 views

Do I need a ground plane?

I'm a noobie in pcb designing, so i created this one single sided board, do i need do add a ground plane if I have a ground trace? Cheers!
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1answer
37 views

Custom board cutoffs pcb

I have been playing with the board shape, im planning to send this to OSH spark for manufacturing, however i have doubts about if they can do cutoffs of the boards like this or any other possible form ...
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2answers
299 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
37 views

Altium 3D not showing textures

i Finished my design and now im trying to make it fully 3D with STEP 214 models formwww.3dcontentcentral.es however as you can see even when im gettign the right models they just look like this, when ...
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2answers
36 views

Silkscreen covering pads

Im prepparing my 1st pcb for manufacturing, and before i generate the gerbers i wanted to ask some things here fist, What happens when i put a silk screen like this? a logo big enough to cover the ...
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1answer
46 views

Validation of power supply decoupling and oscillator connections in a PCB

I've been learning PCB designing lately to design a small controller board.The board has a micro-controller and its supporting components laid out as shown : . After having gone through some nice ...
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3answers
80 views

Via's in switch mode power supply

I'm using a TPS54386 and currently designing a PCB layout. The data sheet says to avoid via's within a certain loop; I was wondering what would happen or if anything would if I went ahead and placed ...
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1answer
55 views

High failure rates after pcb coating using DC 3140 RTV

We have been protecting PCBs using Dow Corning 3140 for many years now without any problems. Last couple of months however, one board after the other is failing after coating. We can't think of any ...
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0answers
37 views

IFA PCB Design Concern

The question that came to my mind once I did the tracing is , should I place a ground plane in the bottom layer of the PCB only and make the IFA trace in the top layer and then place a via in the head ...
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0answers
35 views

No Clean flux pcb corrosion

This is a follow up on my earlier question. earlier question In summary, I have noticed corrosion on some of my boards and I am trying to decide if I should scrap the whole batch or try to salvage ...
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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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2answers
68 views

How would I use the same component arrangement for each instance of a sheet symbol?

I'm designing a PCB using Altium. I am a beginner and I'm using sheet symbols to design 6 identical circuits. Making a billion circuits with identical schematics is easy, but in order to make the PCB ...
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5answers
2k views

Why does there seem to be a missing component in many PCBs?

I've seen some PCBs were some components have been sketched, but they don't seem to be mounted on the board. See, this image (of a PlayStation 2) where the transformer has been drawn: Why is this ...
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1answer
62 views

How to draw an elliptical PAD in Eagle

I am trying to design a PCB layout for a component which requires elliptical pads. I am trying to do it with two arcs but I didn't get an ellipse. Can anyone suggest how to draw ellipse on eagle? Is ...
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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 ...
3
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1answer
110 views

Mold (Fungus) build up on PCB

I have been running small batches of production over a year without a problem. Today, I found a problem that is never happened before. I have changed the PCB to gold plated in my recent batch and I ...
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2answers
91 views

How thick a gold finish on a pcb for wire bonding?

As a partial reparation for my previous question today. Please allow this rather esoteric/ but on topic question. I was sending out a pcb that will have gold wire bonding pads. It was a option at our ...
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2answers
75 views

Soldering problem when changing component on tablet board [closed]

I needed to change demaged Schottky SMD diode (2.2x1.2mm) at chineese tablet board. But I was not able to melt solder even I used hot gun at 400°C or soldering tip at 480°C. Finally I more or less ...
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1answer
99 views

How can I solder LCD Pins when solder does not “stick”?

I have a 16 * 2 LCD Display, with 16 input pins. However while I am soldering the pins it it does not stick or "take". How can I fix this? Is there any other metal for soldering a display ?
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1answer
36 views

How to draw pin grid array in cadsoft Eagle pcb?

I'd like to use a processor that uses a pin grid array. Basically, I'd like to make the prototyping PCB board for it. I'm new to eagle so I made an attempt to do this, and this how it looks like. Q1) ...
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1answer
403 views

How to select FR-4 board thickness

The PCB manufacturing house that I use says the board thickness between 0.4mm and 1.6mm are the same cost (I have 2 layer design). What is the benefit of having thinner or thicker board thickness for ...
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1answer
64 views

What is the proper zero orientation for a SMT LED?

What is the proper zero orientation for a SMT LED? According to screaming circuits and IPC-7351, the cathode should be on the left for a molded diode. HOWEVER, when I use Altium's component wizard to ...
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1answer
85 views

Placing Via's on PCB

I'm designing a PCB for USB 3.0, the specifications for Differential impedance comes at 90 ohms with a tolerance of +- 5 ohms. I've used different calculation tools but when I have to hold these ...
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2answers
136 views

How to get the square wave output at Photodiode

LED flashing light captured by camera Displayed image detected by Photodiode I have a 2V p-p square wave signal of 500µs. This signal drives ...
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0answers
53 views

Can a USB 5v 0.5A powered pcb sent data to a 3,5 mm jack using a 2nd usb port via usb-to-3,5mm converter wire?

I am designing a MCU for a device that is powered by USB. This device needs to send simple serial commands to an 3.5mm stereo port on a monitor. The wanted to use USB-to-3.5mm jack converter wire, ...
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1answer
85 views

Identifying power and ground in a PCB

I have a PCB from a control box for a machine. It's conmected to the machine via a DB25 cable, and gets power over the cable. How can I identify the power and ground pins on the cable? If it helps, ...
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1answer
57 views

Is there some PCB tool that exports to ISIS Proteus [closed]

I'm a CS student and I have to build a project in ISIS Proteus as a semester project, but Proteus' demo version does not allow to save the project. The project must be in Proteus because it is the ...
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2answers
594 views

Why are some mounting holes connected to ground?

Why are plated mounting holes connected to ground ? I read that if you are connecting your board to chassis ground, then it should be connected at only one point and connecting say 4 mounting holes ...
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97 views

Bench power supply adaptation 13.8V min to 12V [closed]

I have a bench power supply, which gives a minimum of 13.8V with 20A. There is something to do for adapting this scheme to give a minimum voltage of 12V? The scheme is this one ...
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2answers
269 views

Why we need the PCB Panelised for assembly?

I have a PCB finished in invidividual size for customer but they gave me comment that it can't be used by their assembly vendor and ask me make the new batch for them, When we make the board in 2 up ...
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0answers
39 views

PWM and flyback diode dependency

I have to choose components for a pcb motor driver, there is a dependency that I have to take into account between the PWM frequency and the speed of the flyback diode? If yes, what it is? Thanks
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6answers
2k views

What is the purpose of a PCB with no copper tracks, but only unconnected copper rings?

I have a PCB which has the perfect size for a project of mine, so I would like to use it if possible. However, the copper plating on the back side of PCB only surrounds the individual holes (that is, ...
3
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6answers
357 views

Manually Drill Vias into PCB

As shown in the photo below, the PCB design was sent for fabrication without the drill data. Is it still possible to drill the via holes so we can save the PCBs? This is a 2 layer board, most of the ...
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3answers
114 views

Eagle: Remove some text of a compoment label

I routed a small board that will get connected to a BeagleBone Black using two 8x2 pin header connectors. As you can see on the picture there's two labels that are drawn out of the board layout so ...
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26 views

Advice: how to integrate minipci cards to a board design

I'm designing a pcb card for one embedded device based on a Digi iMX28 module. In the design we included a couple of minipcie sockets to add 3G and wifi cards. However, there are two flavors of ...
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2answers
60 views

Any simple power supply designs for a 24VAC transforrmer?

I'm a beginner in Electronics Engineering. Any suggestions on simple power supplies with PCB designs which are run by a 24VAC transformer? Thanks!
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1answer
38 views

How to make Eagle package with dual row surface mount tails?

I'm doing a project using the OMNETICS dual-row connectors (http://www.omnetics.com/neuro/pdffiles/A79025-001.pdf). I'm a bit lost about how to make the package for it in Eagle, as the connector has ...
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0answers
59 views

Tango PCB Designer

i'm trying to run the old Tango PCB on a DOSBox, on windows 8.1. I did the same things to make it run that i did on windows 7, but it's not working on windows 8.1, have anyone tried to run Tango on ...
3
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0answers
50 views

How to clean “no clean” flux with a 3L ultrasonic cleaner

I am doing some small batches of PCBs, like 100 each time, using solder wire with no clean flux core. I am using this solder wire ...
5
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3answers
554 views

Will solder usually connect copper vias on a 2-sided PCB?

I've seen videos where the board is suspended in a solution with an applied voltage to plate the vias, but I don't really have the resources to do that. Is soldering parts a reliable method to ensure ...
7
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3answers
855 views

What to do with unused pin?

I am designing the Vishay VCNL4010 proximity sensor into one of my PCBs. This sensor has an interrupt pin that I don't need to use. Is it OK to just leave this pin floating ("unconnected"), or will ...
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0answers
75 views

What is this motherboard component that looks like a bead of solder [photo], and can it be repaired/replaced? [closed]

As you can see, the one on the top is burnt. Whenever I plug the power adapter into the wall, the component releases a puff of smoke and the adapter instantly shuts itself off. The damage to the ...
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3answers
61 views

PCB trace width calculation

Take a look of this product: http://www.hobbyking.com/hobbyking/store/__68694__HK_Pilot_Power_VI_Module_Distribution_Board_And_Dual_UBEC_ALL_In_One_120A_and_10s_.html It says is a 45 by 45 mm PCB, ...
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2answers
103 views

How do I solder to these pads?

Quick question. I'm trying solder some wires onto the 5 pads (top right of board) in the image. What's the best way to achieve this? I cant get the solder to stick to the board and I have no flux. I ...