Questions tagged [design]

The process of creating electronic products, including components and end-user devices.

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74
votes
6answers
43k views

Ceramic caps vs electrolytic. What are the tangible differences in use?

A quick google around and all I seem to be able to find are people talking about the physics & the chemistry of the capacitors but not how this affects choosing which to use. Avoiding talking ...
51
votes
3answers
13k views

What's this importance of datasheets?

As someone starting with electronics I keep hearing, "Check the datasheet!" Why are datasheets so important and what information can I expect to find in them? It seems like a large amount of ...
48
votes
3answers
13k views

How to go from a development board to a production board?

Ok, I am a software guy and new to electronics. My product needs a small computer and currently I have developed everything on development boards like raspberry pi and such. As the development board ...
44
votes
15answers
10k views

What are low cost circuit and PCB design software? [closed]

Do you know of any freeware or low cost circuit / PCB design software? I know a few which I have listed below but I was wondering if there were more of its kind. Please mention the good features and ...
43
votes
7answers
7k views

How do you document your hardware design decisions?

How do you document your hardware decisions in the design phase? How do you avoid having to ask yourself the following questions while reviewing an hardware design that you made in the past: Why did ...
41
votes
5answers
60k views

Stripboard/veroboard/matrix board design software

I'm prototyping a simple layout for a small project on matrix board, but figured there must be a better way than drawing it all out on paper. Are there any aimed at matrix board? I've found the ...
40
votes
18answers
13k views

What are good microcontrollers available today? [closed]

I have experience with assembly and C programming for microcontrollers, but I'm not familiar with the various MCU and DSP families offered by today's companies. (eg: Texas Instruments, Atmel, Renesas) ...
34
votes
6answers
2k views

Why is open hardware so rare? [closed]

I'm trying to understand why open hardware is so much harder to come by than software. I've tried looking around online and I couldn't find as satisfactory explanation. I understand that hardware is ...
34
votes
4answers
34k views

Make a custom plastic case

I have worked on many electronic DIY projects like MIDIbox (http://www.ucapps.de/), it always was fun and working but at the end, the problem was that I ended with a cool gear, but in a poor casing, ...
33
votes
7answers
4k views

Is circuit design based on min/max values good practice?

Time and again I am arguing with a colleague of mine about the question above. When I design a circuit for mass production (> 10k/a) I want to make it robust against every possible variation of ...
31
votes
11answers
16k views

What is the most amazing PCB artwork you've ever seen?

Have you ever looked at a PCB and burst out laughing? Have you ever looked at a PCB and said "Wow, that is amazing"? Have you ever seen a PCB that artistically expressed criticism of society's ...
29
votes
5answers
2k views

Design Calculations for the Seasoned EE

Do seasoned designers tend to do a fair amount of calculations or are large parts of circuits designed intuitively? I'm asking because it seems like design engineers tend to have a sense of what value ...
27
votes
10answers
13k views

How do I power/wire something that is rotating constantly WITHOUT extra batteries?

So I want to make a Lazy Susan that is rotating constantly in one direction. I also want to have some other things on top such as neon signs, moving things, and etc. Problem is I want this to all run ...
26
votes
5answers
4k views

Why do some EMI/RF shields have holes on the top and some don't?

I am not talking about cutouts for tall components. I don't think they are for ventilation as they are often covered with manufacturer labels.
26
votes
5answers
5k views

Making a battery last a long time in a microcontroller circuit

I'm hoping to power an ATtiny85V for a nice long time on some small battery, probably a coin cell. I've looked into the software side, and my code is watchdog timer driven, has unused analog and ...
24
votes
5answers
3k views

How are circuits which use complex ICs normally simulated?

I understand that it is common practice in electronic design to simulate a circuit in some spice program before building it. Sometimes a project requires the use of complex ICs, for instance an IC ...
24
votes
4answers
2k views

After PCB layout

After you've designed your circuit and have the PCB layout completed, how do people in the EE industry go about designing the enclosure? What kind of considerations need to be made to accommodate the ...
24
votes
7answers
4k views

SMD vs. Through-hole components in high vibration environments

This is more of a opinion question than a information question. I am designing some boards that will be working near decent sized actuators, so I ask you, what is more resistant a 0805 SMD or a 7mm ...
24
votes
4answers
11k views

How do you determine how much flash/RAM you need for a microcontroller?

Let's say you are starting an embedded project with some known functionality. When you select a microcontroller how do you select how much RAM you need? Do you use a developer board and code your ...
24
votes
7answers
3k views

One large microcontroller, or lots of small microcontrollers?

I'm used to doing basic and straightforward things with microcontrollers, relatively speaking. Things such as driving LEDs, running motors, basic routines, GUIs on character LCDs, and so on, but ...
22
votes
6answers
33k views

Internal or external oscillator

I always use the internal oscillator that pics have as I have never found the need to run anything at higher frequency than 8 MHz (which is the fastest the pics I use tend to be able to go). Are there ...
22
votes
4answers
2k views

Do engineers still design for volume using discrete through-hole bipolar transistors?

As a hobbyist who likes plugging BJTs and discrete components into solderless breadboard for entertainment and education, I recognise that people like me are an insufficient market to make it ...
21
votes
6answers
2k views

How do you structure large embedded projects? [closed]

Background: Junior R&D electronics engineer (the only EE in the company) - the hardware and the coding is not the problem. My biggest issue is getting a proper overview of the project, and where ...
21
votes
6answers
13k views

New to PCB design - why doesn't auto placing components exist?

The circuit design software I have seen has the ability to automatically route traces etc. on a PCB. But why doesn't this software have the ability to automatically place components on a PCB say to ...
20
votes
3answers
11k views

How are CPUs designed?

I've started playing with electronics a while ago and making simple logic gates using transistors. I know modern integrated circuits use CMOS instead of transistor-transistor logic. The thing I can't ...
19
votes
3answers
5k views

Getting started with PCB Layout for BGA Packages

Are there any good resources for learning the intricacies of PCB layout when dealing with BGA packages? I'm very familiar with layout for almost every SMT part that has leads on the edge (QFP, TSSOP, ...
19
votes
2answers
3k views

Industry Practices for Schematic Design?

As my designs (and PCB designs too) become more complicated, I'm interested if there are best practices or industry standards for schematic design. I know there's a schematic checklist but I'm looking ...
18
votes
10answers
5k views

Circuit Simulation Software [closed]

I'm getting back into hobbyist electronics after a very long hiatus and was wondering what the current state of circuit simulation software is. What is the industry standard for macs or PCs? What are ...
18
votes
4answers
3k views

analog circuit design resource recommendations

What are some excellent resources related to advanced analog circuit design? This includes RF, sonar, audio, low-frequency, high power, low power, noise, amplifiers, etc.. To get the most obvious ...
17
votes
6answers
5k views

Why don't three-phase transformers use toroidal cores?

When looking at different transformer core designs, three phased, I never see any core designed as a circle or torus. Why is that so? Will it not work as well as the common B-shaped core?
16
votes
6answers
6k views

Why implement microcontroller in FPGA?

I am currently "investigating" FPGAs, what they can do, how they do it etc. In more than one place (for example here) I have seen projects that implement a simple microcontroller with FPGA. So my ...
16
votes
7answers
1k views

What process do you use to ensure your PCB works on the first try? [closed]

What are the best practices for catching stupid mistakes vs more subtle ones? Do you run over a checklist of things for each design? If so, what kinds of things are on it? I'm interested in ...
16
votes
8answers
14k views

Ideas to stack multiple PCBs on top of each other?

My design has a number of boards stacked on top of each other. I would like to connect signals across the boards. The boards all need the same 10 signals running through them (all boards from top to ...
16
votes
5answers
2k views

Possibilities for allocating memory for modular firmware design in C

modular approaches are pretty handy in general (portable and clean), so I try to program modules as independent of any other modules as possible. Most of my approaches are based on a struct that ...
16
votes
6answers
38k views

Inductors - what are they used for? [closed]

When are inductors really used? I have read that the elements are typically quite hard to implement into circuits given their physical characteristics. I also read that if inductors are placed in ...
16
votes
5answers
40k views

What are the best free schematic tools out there? [duplicate]

I'm sure there are plenty of schematic tools available. Which ones do you use/prefer? Feel free to also list tools which aren't completely free but very popular.
16
votes
6answers
811 views

How can I evaluate or speculate on a part's production lifetime for long term part sourcing?

Suppose I have an idea for a product, where if it were successful, would be in production for 5-10 years. How can I make decisions on what parts to use now such that they will still be available to ...
16
votes
3answers
849 views

Is it possible to have too much decoupling?

In most of my designs recently I've been quite liberal in using decoupling caps (especially 0.1uf X5Rs) on most if not all of the supply pins for anything that performs some remotely significant ...
16
votes
3answers
9k views

How to implement a soft power switch controllable by microcontroller?

I want to design a circuit such that the microcontroller can toggle a GPIO pin and shut the whole system (including microcontroller itself) down. And when the user presses a momentary button, the ...
16
votes
1answer
2k views

Analyze My Homebrew Diplexer

I'm in need of a diplexer that'll separate RF signals from a single feedline to two antennas. What I designed and built was a diplexer that would allow ~38 Mhz and below out port 1, with ~38 MHz and ...
15
votes
4answers
16k views

What is metastability?

From the Wikipedia article Metastability in electronics: Metastability in electronics is the ability of a digital electronic system to persist for an unbounded time in an unstable equilibrium ...
15
votes
5answers
1k views

Voltage regulator from first principles - why is power dumped in the transistor?

I'm trying to further my understanding of electronics, so I decided to try to design a fixed voltage regulator capable of supplying an amp or so. I put this together from first principles without ...
14
votes
7answers
5k views

LEDs on a (battery) budget! – How can I lower the current through a LED without using up the battery?

EDIT: Here is a much brief version, the meandering motivated version is probably subsumed in the parent question on general battery life optimizations. How can I lower the current into a LED ...
14
votes
4answers
979 views

How can I go from prototype to commercial product?

I have made many designs that I would consider "professional grade", but in reality they are still just prototypes. I have used professional board fabs and professional population, but what I haven't ...
13
votes
4answers
3k views

At what level of complexity should I consider UL listing my widget?

I am interested in making a widget to sell, but it will probably have a small market and small volume. At what level of complexity should I consider UL listing (or otherwise certifying) my widget? I ...
13
votes
4answers
1k views

From C to Silicon: How to implement software/firmware solution as hardware?

In light of this question, I was wondering if there was a fairly standard process for turning a software solution into a hardware implemention. Forgive me and my imagination, but would there be a ...
13
votes
2answers
52k views

how to select capacitor values

I am trying to find information on formulas used to calculate capacitance required for a given circuit. Not a circuit in particular, just in general how to figure out what value should be used. I know ...
13
votes
5answers
15k views

Why does active low even exist?

In my career I've often encountered signals that are active low (Reset being the most common). I've even seen interfaces where all control signals are actively low. To me, this is very unintuitive ...
12
votes
4answers
1k views

How reliable are application notes

My last question brought up some discussion about application notes and (bad?) practice. See the comments under the various answers. Until now I thought: "Ok these application notes are written by ...
12
votes
4answers
4k views

Why do I suck at electronics so much? [closed]

I have always been interested in electronic circuits since 3rd grade when we lit a bulb up. I then always wanted to learn more and more. I'm a soft-more in high-school and  it seems like i've it a ...