About designing the boards which carry the components of an electronic circuit. For questions about getting them built instead use PCB-fabrication. If your question is specific to a certain CAD tool, say which tool and version you are using.

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2
votes
2answers
36 views

Can I make a double board at smart prototyping pcb service?

They have a 5x5cm minimum board size. My board is approx. 35x20mm so I can easily put two side-by-side and thus double the board count within this limit. What is the best way to do this? I know how to ...
0
votes
0answers
41 views

Can I use General Purpose Printed Circuit Board for any voltage or current rating?

The thickness and width of the copper pad (1 ounce/ 2 ounce) depends on the current that will pass through it. Can the General Purpose PCB withstand high currents (up to 15/20A)? If not, is there ...
0
votes
1answer
71 views

What constitutes a Via-in-Pad?

Would any of the via's in the picture be considered a via-in-pad? or is it only if it's dead center of the pad?
11
votes
4answers
878 views

Why is it so hard to find component footprints?

When designing PCB's, I find myself very often having to make footprints for a significant portion of the components on my board. This tends to be very time-consuming, as (in Altium at least), ...
0
votes
0answers
29 views

how to create connectors for hollow pad in Fritzing

I have manage to create a circular hollow pad that I want around a PCB. Now I would like to add the connectors so I could attach parts to it and I could not manage to open the file in Fritzing part ...
9
votes
3answers
861 views

What does a race condition mean?

I'm a new electrical engineer so bear with me. I hear some of the other engineers I work with talk about a race condition that exists in one of our circuits. What does that mean?
1
vote
0answers
49 views

Reused MCU unit does not work

I had a board with ATMEGA16 (SMD package) micro controller and I had to program through ICSP and it was working fine. Later I needed to make some changes on the board. So I designed a new board and ...
1
vote
3answers
67 views

PCB Holes Too Small to Fit Component

Based on the VSK-S25 datasheet which states the holes to have a diameter of 1.5 mm, I used the following values in EAGLE When the PCB is made, it turns out that the pins of VSK-S25 are too ...
0
votes
1answer
30 views

Two 2.4GHz radio modules (XBee+Bluetooth) on same PCB. How to minimize interference?

I'm designing a PCB with XBee radio module and a bluetooth module (RFDuino SMD with XBee 2mW Radio). Since both of these modules are using 2.4GHz, are there any special consideration about how to ...
0
votes
2answers
61 views

VSSOP-8 Package Footprint

I am trying to create a footprint for a LMR61428 but the datasheet (linked) only has the package outline and nothing for the recommended land pattern, or footp for a PCB design. I found this image on ...
14
votes
3answers
2k views

Why are vias bad?

I am designing a PCB with EAGLE and saw that it was trying to limit the amount of vias through the PCB. Why do you want less vias? Why are they bad? Do they bring extra manufacturing cost or is it ...
0
votes
2answers
38 views

Function of undocumented pads on PCB mount power module

I'm hoping someone may be able to explain to me why are there extra pads on the bottom of APXW003 DC/DC SMPS PCB mount module from ProLynx series from GE Industrial. I am doing a design and it turns ...
0
votes
3answers
65 views

Autodesk Autocad for PCB design

I recently completed an Advanced Diploma level course subject for PCB design that taught Autocad as the design software. Whilst I am aware of the power of Autocad my subsequent surveying of ...
0
votes
3answers
85 views

PCB design few questions

Quick couple of questions, I am designing my first PCB and want to have a few boards prototyped with OSH Park. For a board I will be manually soldering components to, will I need to include a tCream ...
0
votes
1answer
23 views

Altium Design Rule - Selecting Pads Whose Parent Component is not type “No BOM”

I can create a query to select only pads and a query to select only components who are not type "No BOM", but I can't seem to find a way to put these together to create a design rule that only selects ...
1
vote
2answers
338 views

Weird capacitor looking things shows up in altium when I zoom into the pcb layout

I am using altium for first time for my little circuit project. My layout start showing these weird capacitor looking things in PCB layout. What exactly are they and what are they used for and how do ...
0
votes
0answers
37 views

Trace clearance error with Altium auto-route

Here is the picture of my PCB auto-routing result. Routes are placed too close to SMD pads. Less than 0.2 mm, which written in Clearance rule. I use Altium Designer 14.1 so I can't set clearance ...
0
votes
0answers
118 views

How to simulate Arduino? [migrated]

QUCS is the only open source software which offers simulation (and designing PCB layout [in future]) of electrical circuits. But the problem with QUCS is that it is under development and many ...
3
votes
1answer
52 views

Rotated component placement in Altium

Here Altium PCB on the picture. I rotate component on 45 degree and place it on the PCB. What is gray area under the component? Should it be rotated also? Can it be a problem if it s not rotated? ...
0
votes
1answer
55 views

Eagle will not finish auto routing?

Using Eagle for mac, I am trying to autoroute the board. I have set the trace width to 8. He start the process and it takes him about 2 minutes, than he stops at some point and show the next ...
0
votes
0answers
30 views

No trace in the pcb gerber from Eagle?

I use Eagle to create gerber files. Here is the gerber file job : ...
4
votes
2answers
70 views

Design question regarding high current wires running below PCB

I am working on a layout that will look similar (not final) to the illustration below. There are three high gauge wires (red) 3x230VAC passing directly below the PCB (isolation touching the PCB) that ...
0
votes
2answers
68 views

PCB manufactoring-There shouldn't be bottom silkscreen selected?

I use Eagle to create gerber files . When i am trying to check my zip gerber, in 4pcb.com i get this message : ...
7
votes
3answers
426 views

What are the different grounds on a PCB?

I am working with boost converters recently. I have problem which you can find here. After going through the datasheet several times I encountered the special focus on the ground plane. It talks about ...
0
votes
1answer
37 views

Stop mask error upon running DRC in Eagle 7.3.0

I'm working on my first board layout using Eagle (7.3.0). I've got the layout done, but when I run DRC, I get a number of Stop Mask errors: These seem to be due to small rectangles on the tStop ...
8
votes
3answers
775 views

How to cut costs when fabricating large PCBs?

I've looked online at PCB fabrication companies, and they invariably price their boards according to the size of the board as the primary factor. Why is this? The physical board itself isn't that ...
2
votes
1answer
59 views

Crystal Footprint Placement

Pretty simple question, please point me in the right direction if this has already been asked. I am designing a board around freescale's IMX23 microprocessor which runs from an external crystal at ...
1
vote
2answers
90 views

TPS61240 Boost converter IC is not working at all?

I am currently using TPS61240 as a boost converter for my project. As i did not have any sample previously so there was no way I could test it. I ordered the IC and placed it on my final PCB directly. ...
2
votes
1answer
79 views

Is using a ground AND supply pours on a 2-layer PCB a bad design decision?

Ground pour on the top, supply pour on the bottom. Does this typically increase noise? Is it considered a poor design decision? It's certainly makes things easier from a routing perspective to pop a ...
0
votes
3answers
115 views

Printing the self designed PCB

I have designed the PCB on Eagle. Most of the components are SMD pakages. This is for the first time i have designed the PCB. I want to print this PCB in the industry (Chinese industry) but i have no ...
0
votes
1answer
25 views

Removing pad to polygon space in Eagle

In Eagle, is there any way I can remove the empty space around the pad here? I would like the polygon to connect to the whole pad. Note that this is a pad from a part and not a via.
0
votes
1answer
34 views

Question about clearance/pad diameter and PCB design

Sorry if this is a silly question but I am relatively new to Eagle and I am 100% new in dealing with high powered PCB design. So, I am making the footprint for the LEM LV 25-P voltage transducer seen ...
0
votes
1answer
82 views

PCB - High current PTH

Some power boards are failing a high current (lightning) test where an MOV lead is used to transfer the current to the bottom of the board - see MOV lead and pad attached. The issue seems to be that ...
3
votes
2answers
86 views

Precisely drawing component footprints in EAGLE

Whats the recommended way for placing components accurately and quickly when creating EAGLE parts? For example in the drawing below, using grids with 0.01 grids will give us the control needed for ...
0
votes
1answer
41 views

PCB stackup for Mixed-Signal IC

I need to design high-density board with MCU, external RAM, GPS, GSM, Bluetooth, CAN, RGB interface on small size(5x10cm) and got into thinking which stackup should I use. Currently I have almost ...
1
vote
1answer
44 views

Trace Dimensions limitation for JTAG signals

I have a JTAG bus that I need to go over PCB (or could make cable) for about 12 inches. I am trying to figure out the signal integrity specs for the JTAG bus ... what trace width vs. trace length I ...
1
vote
2answers
149 views

Is this pcb layout good practice?

I saw a PCB with something like this. A trace that connects the four holes on the corners. I assume that they do it to prevent some kind of noise. I am not sure if the connect that trace to GND Also, ...
1
vote
1answer
61 views

Decision on connecting Earth Ground to one of Two GND pins

I'm planning to design a board that is suitable for industry so EMC is so important. I have decided to use two separate power supplies(+5v and +24v) to Isolate the board from outside world. ...
7
votes
2answers
766 views

Air gap on isolation space

The below photo belongs to a PSU. I wonder what was the reason of placing air gaps on the 8 mm isolation. Is it to improve the isolation or provide a thermal relief (although there is no component ...
3
votes
2answers
142 views

How to find a way to detect if a device was opened or not

I'm making a device which is inside an enclosure and at this point of the project it's relevant to understand if the enclosure/box was opened. I was trying to understand if I can try to figure it out ...
0
votes
0answers
45 views

Do I have to use Kapton for PCB stenciling? [duplicate]

I am considering the possibility of making my own custom stencils for a PCB. However, Kapton is quite expensive... Is there another material which I can use for stencilling a PCB design?
0
votes
1answer
98 views

Using a Normally Closed PCB mounted Solid State Relay

Summary: Continuing my search for a solution to my problem, I have landed on normally closed solid state relays (NC 1 FORM B SSR). Could you tell me if I'm doing this right? What I need: What I need, ...
-1
votes
1answer
77 views

Understanding parts of this PCB

I am sorry guys that I am not an Expert of PCB and I am still a learner so please answer this question. i want to know which parts have been used in this PCB. this device is used to automatic Starting ...
0
votes
1answer
62 views

What is a safe clearance for ground planes?

I am designing a board and the ground plane default clearance was set to 22 thou. I have been told in the past that a rule to thumb, with signal lines, is to work to "8 thou track and gap" So is it ...
-2
votes
2answers
79 views

PCB Design Software for work collaboration and minor alterations? [closed]

In my workplace I need PCB software to make minor changes to PCB layouts from our design partners and also to review and suggest changes to incoming designs. Our design partners use x and y. X is ...
1
vote
3answers
106 views

PNP Transistor Leak

I have a problem with a circuit that should be simple but has caused me some annoying problems. Summary: I need a switch that closes when the power is off and opens when the power is on. My solution ...
0
votes
0answers
36 views

Using PNP 2N3906 to signal GPIO LOW when negative pulse is detected

http://www.savagecircuits.com/attachment.php?s=04cc498cb970ec62cdb517a60346c629&attachmentid=290&d=1430452949) In the attached schematic +5v input is turned into GPIO Low while 0v input is ...
0
votes
2answers
109 views

Why do circuit boards use strange paths? [duplicate]

First, let me say that I'm no electrical engineer, I'm just a curious student. Here's a photo of a Raspberry Pi A+. I (as one completely ignorant of PCB design) would expect the electrical paths ...
2
votes
1answer
55 views

From what pitch should I consider ENIG finish

My design (4-layer, FR4, 1.6mm) has a couple of ICs with 0.5mm pitch pads and some LEDs with 0.4mm pitch pads, very small LEDs. Should I consider ENIG (more expensive) or will HASL do the job? I read ...
0
votes
0answers
84 views

Tantalum Capacitors to Electrolytics Capacitors/Ceramic Capacitors

I'm trying to reduce costs from my design and one of the things that I'm thinking about is changing the Tantalum capacitors to Electrolytic ones with low ESR. P.eg. I'm applying one Tantalum ...