Questions tagged [design]

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

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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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
1
vote
3answers
1k views

BJT Amplifier with Emitter Bypass Capacitor Design [closed]

I am trying to design a BJT amplifier. The circuit is shown below with its parameters. beta=180 RL=20kΩ VA=0 (early effect can be ignored) VCC=15V There are three constraints listed below: Swing ...
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 ...
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 ...
4
votes
1answer
2k views

The flyback diode and its applications

So in an application like this: The coil of the motor will, by Lenz's Law, induce a very large negative voltage across its terminals (without the diode in place). Would this voltage be very negative ...
4
votes
3answers
2k views

BJT Bias Design and Operating

I'm to the task to design a BJT Common-Emitter Amplifier with resistance at the emitter as in the figure, and for that I need to: get the values for \$R_{1}\$, \$R_{2}\$, \$R_{C}\$ and \$R_{E}\$ ...
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 ...
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 ...
7
votes
5answers
4k views

Learning about electronics

I'm a computer scientist with zero exposure to things directly related to hardware (barring what I learned from my undergrad computer org class.) I've been very attracted to the field of embedded ...
9
votes
3answers
34k views

What are FIT's and how they used in reliability calculations?

In Military, Medical, Space, Professional eqt. design there is a need to be able to prove that your device can last a certain length of time with a certain confidence level. Or that reliability must ...
0
votes
3answers
3k views

Is it possible to build an H-Bridge with only N-MOSFETs (and these other components)?

I am trying to design an H-bridge circuit and I am only given the following components: Opamp Zener Diode Resistor Capacitor N-MOSFET NPN BJT Diode 2-input NOR 2-input NAND Infra-red Detector Infra-...
2
votes
4answers
43k views

Construct an 8k X 32 ROM using 2k X 8 ROM chips

Construct an 8k X 32 ROM using 2k X 8 ROM chips and any additional required components. Show how the address and data lines of the constructed 8k X 32 ROM are connected to the 2k X 8 chips. I ...
1
vote
3answers
7k views

Frequency Detection Circuit Design

I want to create a circuit that can detect audio frequencies and flash RGB LEDs different colors depending on the detected frequency. The frequency range will be from 20 Hz to 12 kHz, after looking at ...
0
votes
4answers
247 views

Automatic switch using LDR

I've implemented above circuit and it was successful. The given circuit needs 12VDC to run properly. I want to run this circuit on 5-6VDC or 9VDC whichever is possible. I know I have to change ...
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 ...
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 ...
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 ...
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 ...
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 ...
12
votes
3answers
2k views

Getting started with PCB designing

I'm a hobbyist EE in college, and have been building breadboard circuits and perfboard circuits for the past year or so. I want to move on to doing PCB design. I wanted to start with something small ...
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.
3
votes
3answers
4k views

How to test and rate a home-built low dropout regulator?

I built a low dropout regulator following experiences building a discrete linear regulator. The circuit is simple like this: simulate this circuit – Schematic created using CircuitLab I would ...
1
vote
4answers
4k views

How to measure the component value on a PCB?

I have faced a few instances in which I need to measure resistor or capacitor value which is soldered to the PCB board (SMD component). These are very small and difficult to look the value written on ...
8
votes
2answers
6k views

Driving a LED from a wide ranging input voltage

I have been working on a small linear power supply, capable of regulated output between 2V to 30V, using the LM338 IC. For the most part it is a simple implementation taken straight from the datasheet....
0
votes
1answer
565 views

Designing an Oscillator

I'm tired of having to resort to Google to find every single oscillator design. I would usually just try to search for a circuit using the same frequency crystal, and try to build that. Right now, I ...
6
votes
2answers
6k views

Beginner information related to constant current dummy loads

I am beginning an electronics design project to build a constant current load to drive testings for batteries, bench power supplies etc. I have been hard trying to locate some black-on-white ...
4
votes
1answer
2k views

MOSFET H-bridge design

given the circuit below to be used as a H-bridge with AVR PWM. Is this a good desing to use? What can you recommend? I already built something like this but without the resistors. ( and so burned ...
3
votes
3answers
1k views

Electronically switched decade resistance box design

I'd like to design a decade resistance box that uses a microcontroller to control the resistance. Would it be possible to switch between different valued resistors using transistors? (or another ...
2
votes
1answer
5k views

ICs that convert an AC signal into its true rms value

I need to convert the instantaneous voltage output from my current transducer to a true RMS voltage output. Can anybody please suggest an IC that can perform this function.
2
votes
1answer
7k views

Serial Adder vhdl design

I've a design problem in VHDL with a serial adder. The block diagram is taken from a book. Since i'm not skilled enough in design with clock (except some silly flip flop i've found on the web, and ...
1
vote
1answer
2k views

Altium de-highlighting nets after using 'Find Similar Objects…' command

I can't work out why Altium is doing this, or how to undo it, or how to make it stop doing it. It happens when I use the 'Find Similar Objects... ' option; all of objects that it hasn't found are ...
11
votes
1answer
1k views

What are these spots on the PCB that are by the mounting holes?

When you look at the board, there is a weird part of the PCB right of the top left mounting hole. There is also another one above the top right mounting hole. ****...
8
votes
4answers
18k views

How do I build a bracelet that vibrates once every n minutes? [closed]

I intend to establish a few new personal habits that eventually become second-nature to me. To assist myself, I want to wear a bracelet that vibrates every, say, 5 minutes all throughout the day as a ...
4
votes
2answers
562 views

Symmetric power sockets – design considerations in electrical devices

There are various single-phase power socket standards in use. Some countries use plugs that can be plugged in the socket only in a specific orientation (for example, the United Kingdom) while other ...
2
votes
1answer
32k views

Design a 3-to-8 Decoder Using Only Three 2-to-4 Decoders

Using only three 2-to-4 decoders with enable and no other additional gates, implement a 3-to-8 decoder with enable. The inputs of the resulting 3-to-8 decoder should be labeled X[2..0] for the code ...
2
votes
3answers
6k views

Square Wave Amplifier - 5VDC -> 13VDC

I want to have a square wave that goes from 0 VDC to 5VDC go through some sort of amplifier and that amplification takes that same wave ( at a frequency of 1200Hz but could also be adjusted later ) ...
2
votes
1answer
457 views

Wireless water level sensor, in sump. Installation best-practices for longivity

My wireless water-level sensor is working fine, and when deployed in the sump-well, it is giving me periodic readings quite well. At this stage, I have the circuit still on a breadboard, and now plan ...
1
vote
1answer
120 views

I can't find the values of the currents

The picture below is on page 7 of the datasheet of TL497, it is a switching regulator that I use as an inverting regulator (it has an inverting mode) to generate -24V from 12V in input, in the first ...
0
votes
2answers
11k views

Number of bits for tag, index, and block in a direct-mapped cache

Suppose you have a 64-byte cache on a system with 16-bit memory addresses. If the cache is direct-mapped and it has 10 bytes of tag overhead in total, how many bits are used for the tag, index, and ...
0
votes
1answer
59 views

LCD Gasket Causes Touchscreen Issues

Edit: Pretty much all conjectures in my question have been proved to be incorrect. I started fresh with a new approach. New question is here. Original question: I'm having an issue with a ...
0
votes
1answer
2k views

Designing State Diagram for a 2 input sequence detector

For a lab exercise I have to design a 2-input sequence and Im struggling with the state diagram, as It has 2 inputs, i've designed it with one input before. the sequence to be detected is 1032 which ...
8
votes
3answers
5k views

custom FPGA PCB Design tips

I am planning to design a custom FPGA PCB. the PCB will contain sensors. I need to read the output of the sensors and process them in the processor. I have completed many projects using FPGA's, but ...
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 ...
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 ...
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 ...