178
votes
3answers
29k views
What is it that strips vocals from audio when a 1/8" audio jack is partially unplugged?
Every once in a while, my eighth-inch audio jack will slip loose and I'll seemingly lose only the voice part of a track -- leaving somewhat of a "karaoke" version. What I would guess about how audio ...
172
votes
36answers
55k views
Basic Electronics Book
I need basic electronics books (diodes,transistors,current..etc) as I am just starting out with electronics and want to have something to read over the holiday.
Any suggestions of good beginners' ...
167
votes
28answers
48k views
Good Tools for Drawing Schematics
I was going to add a bit of information to my post on a previous day using schematics and some instructions. What programs are being employed for this purpose.
I mostly want to see what others are ...
151
votes
3answers
38k views
Rules and guidelines for drawing good schematics
We see a lot of poorly drawn schematics here. A few times people have actually asked for critiques of their schematics. This question is intended as a single repository on schematic drawing rules ...
139
votes
8answers
14k views
Why does USB have 4 lines instead of 3?
USB specifies 4 pins:
1. VBUS +5V
2. D- Data-
3. D+ Data+
4. GND Ground
Why is this not 3? Could the Data and Power not share a common ...
119
votes
4answers
118k views
Choosing power supply, how to get the voltage and current ratings?
Power supplies are available in a wide range of voltage and current ratings. If I have a device that has specific voltage and current ratings, how do those relate to the power ratings I need to ...
118
votes
8answers
93k views
What is the difference between Vcc, Vdd, Vee, Vss
I've seen lots of schematics use \$V_{CC}\$ and \$V_{DD}\$ interchangeably.
I know \$V_{CC}\$ and \$V_{DD}\$ are for positive voltage, and \$V_{SS}\$ and \$V_{EE}\$ are for ground, but what is the ...
118
votes
6answers
11k views
Designing a Santa alarm (honestly)
You read the title and that's what I am trying to do.
Synopsis: I have a young son who is determined to catch Santa (to what ends I don't know). He even dreamed up using some kind of pressure plate ...
115
votes
7answers
97k views
Why was Mini USB deprecated in favor of Micro USB?
Mini USB connectors were standardized as part of USB 2.0 in 2000. In 2007, the USB Implemeters Forum standardized Micro USB connectors, deprecating Mini USB connectors four months later.
Why? What ...
107
votes
9answers
30k views
Decoupling caps, PCB layout
I guess I've been somewhat ignorant when it comes to the finer details of pcb layout. Lately I've read a couple of books that try their best to lead me on the straight and narrow. Here is a couple of ...
100
votes
12answers
40k views
What's the difference between a microcontroller and a microprocessor?
What's the difference between a microcontroller and a microprocessor?
97
votes
15answers
40k views
Is C++ suitable for embedded systems?
A common question, here and elsewhere. Is C++ suitable for embedded systems?
Microcontrollers? RTOSes? Toasters? Embedded PCs?
Is OOP useful on microcontrollers?
Does C++ remove the programmer too ...
96
votes
12answers
5k views
How does the current know how much to flow, before having seen the resistor?
With the following circuits as examples :
and
How will the current I know how much to flow?
Would any other wave travel first in the circuit and then come ...
92
votes
7answers
11k views
What measures should I take to protect the USB ports of my PC during development of a USB device?
I'm going to start developing a USB 1.1 device using a PIC microcontroller. I'm going to keep one of the USB ports of my PC connected to a bread board during this process. I don't want to destroy my ...
91
votes
13answers
78k views
What is a decoupling capacitor and how do I know if I need one?
What is a decoupling capacitor (or smoothing capacitor as referred to in the link below)?
How do I know if I need one and if so, what size and where it needs to go?
This question mentions many ...
87
votes
6answers
6k views
What is the reason that the value “47” is so popular in electrical engineering?
We often see component values of 4.7K Ohm, 470uF, or 0.47uH. For example, digikey has millions of 4.7uF ceramic capacitors, and not a single 4.8uF or 4.6uF and only 1 listed for 4.5uF (specialty ...
85
votes
8answers
21k views
Best One-Off DIY PCB Creation Technique
I have finally built up a lab to design electronics in. I have quite a few designs I would like to test. I have tried the printer toner/iron technique a few times but have found that I cannot create ...
83
votes
13answers
22k views
Measuring feline capacitance
When I pet my cat, and then touch her on the nose, I get a little shock. Sometimes, when she walks up to something, her nose sparks and she jumps back and puffs out. I was wondering how I might go ...
75
votes
5answers
5k views
Can microcontrollers be run at arbitrarily low clock frequencies?
The datasheet for the ATTiny13A, for instance, lists Min frequency of 0 MHz. Does this mean the clock can be run at any arbitrarily low frequency with no ill effects? I'm assuming it draws lower ...
74
votes
8answers
34k views
How much does it cost to have a custom ASIC made?
I have browsed several ASIC manufacturer's webs, but I haven't found an actual number.
I assume there would be a fixed cost associated with creating masks and such and then there will be a cost per ...
73
votes
10answers
17k views
Why are there no 256-bit or 512-bit microprocessors?
In an 8-bit microprocessor its data bus consists of 8 data lines. In a 16-bit microprocessor its data bus consists of 16 data lines and so on.
Why is there neither a 256-bit microprocessor nor a ...
73
votes
6answers
20k views
Should chassis ground be attached to digital ground?
I'm working on a PCB that has shielded RJ45 (ethernet), RS232, and USB connectors, and is powered by a 12V AC/DC brick power adapter (I do the 5V and 3.3V step down on board). The entire design is ...
68
votes
3answers
16k views
How can I efficiently drive an LED?
I understand that I can not connect an LED directly to a battery because it will draw too much current. Thus, there must be something else in the circuit to limit the current. What options are there? ...
67
votes
5answers
23k views
My linear voltage regulator is overheating very fast
I'm using a 5V/2A voltage regulator (L78S05) without a heatsink. I'm testing the circuit with a microcontroller (PIC18FXXXX), a few LEDs and a 1mA piezzo buzzer. The input voltage is ~24V DC. After ...
65
votes
10answers
7k views
What's the cheapest way to link a few microcontrollers wirelessly at low speeds over short distances
What's the cheapest way to link a few microcontrollers wirelessly at low speeds over short distances.
I'm looking to keep it ultra-cheap, use common discrete parts and keep it physically small. I ...
64
votes
10answers
34k views
Are solder fumes bad for me?
I do a fair bit of soldering (lead-free). Is breathing in solder/flux/paste fumes actually going to harm me?
Are cheap fume extractors worth buying?
63
votes
7answers
13k views
What limits CPU speed?
I've recently talked with a friend about LaTeX compilation. LaTeX can use only one core to compile. So for the speed of LaTeX compiliation, the clock speed of the CPU is most important (see Tips for ...
61
votes
7answers
9k views
Can a bird, previously at earth potential, get electrocuted by landing on a powerline at high-enough voltage due to the initial “equalization charge”?
At the voltage levels of typical overhead transmission lines in the US, a bird can land on one and be just fine (as long as it doesn't do something like spread its wings and touch a tree or something ...
61
votes
4answers
147k views
What are the different types of solder used for?
How do I know when to use lead, flux-core, lead-free, or any other kind of solder out there? Do you have any tips on solder gauge for specific applications?
60
votes
6answers
24k views
What is the difference between a DSP and a standard microcontroller?
I understand that a DSP is optimized for digital signal processing, but I'm not sure how that impacts to the task of choosing an IC. Almost everything I do with a microcontroller involves the ...
59
votes
4answers
71k views
USART, UART, RS232, USB, SPI, I2C, TTL, etc. what are all of these and how do they relate to each other?
As a novice electronics hobbyist, I have heard these terms and more being thrown around everywhere. At its root, I understand that they are all based on communication between devices, computers, ...
59
votes
12answers
7k views
I am a quadriplegic. Would it be possible to power my ventilator humidifier with a battery?
I am an absolute novice in regards to electrical engineering, and so I am hopeful your expertise can guide me in the right direction. I know this is an unusual post for this forum, and so I thank you ...
57
votes
7answers
4k views
Can a circuit be powered from Earth with a return ground on Mars?
Could you use a hot wire (120v 60 hz) from earth and a copper rod inserted into another extraterrestial body (mars) to complete a circuit? If impedance wasn't something to worry about (pretend Mars ...
56
votes
11answers
6k views
How can anyone use a microcontroller which has only 384 bytes of program memory?
For instance a PIC10F200T
Virtually any code you write will be larger than that, unless it is a single purpose chip. Is there any way to load more program memory from external storage or something? ...
55
votes
28answers
34k views
What's the best way to store and categorise resistors/capacitors/ICs/etc?
I did a big cleanup of my collection of parts today and I now have a big pile of parts on my desk (the majority of which is resistors). My previous method of finding the resistor value I wanted was to ...
55
votes
7answers
4k views
Why is my circuit so incredibly sensitive to electric fluctuation?
I recently finished building a circuit showcased in a beginner’s electronics book. I have included the picture of my creation below because I think it may become relevant to the question.
At the ...
54
votes
7answers
73k views
How to get more than 100mA from a USB port
I heard that the current limit for a USB port is 100mA. However, I also heard that some devices can get up to 1.8A from a port. How do you get past the 100mA limit?
53
votes
9answers
6k views
What's so great about ARM?
In a comment to this answer Kortuk asks what the ARM advantage is. I first added some arguments in my answer, but I think the question is interesting enough to be a question in itself, so that more ...
53
votes
7answers
46k views
Tradeoffs when considering SPI or I2C?
What tradeoffs should I consider when deciding to use an SPI or I2C interface?
This accelerometer/gyro breakout board is available in two models, one for each interface. Would either one be easier ...
53
votes
14answers
7k views
My understanding of RC circuits is broken
I asked a relatively simple question. Unfortunately, the answers provoke far more questions! :-(
It seems that I don't actually understand RC circuits at all. In particular, why there's an R in ...
52
votes
6answers
16k views
How many GPS channels make sense?
You need 4 channels to determine your position (including elevation), and I can understand that a few extra channels increase accuracy. However, there are maximum 12 satellites in view at any time, so ...
51
votes
8answers
28k views
Why does a resistor need to be on the anode of an LED?
Please be kind, I am an electronics nub. This is in reference to getting an LED to emit photons.
From what I read (Getting Started in Electronics - Forrest Mims III and Make: Electronics) electrons ...
51
votes
3answers
29k views
How do I calculate the required value for a pull-up resistor?
There are many tutorials that use a pull-up or pull-down resistor in conjunction with a switch to avoid a floating ground, e.g.
http://www.arduino.cc/en/Tutorial/button
Many of these projects ...
51
votes
3answers
6k views
Why are they called breadboards?
Why are solderless protoboards called "breadboards"? I've used the term for decades but couldn't answer a student's question about the name.
51
votes
3answers
14k views
What kind of components are black blobs on a PCB?
In low-cost mass-produced items I often run into black blobs of what looks like resin applied directly on top of something on the PCB. What are these things exactly? I suspect this is some kind of ...
50
votes
9answers
9k views
When to avoid using a breadboard
What are the cases where one should avoid using a breadboard? e.g. high frequency, noise prone circuits etc.
50
votes
5answers
7k views
What is impedance?
This is presented as both a resource for the community and a learning experience for myself. I have just enough knowledge of the subject to get myself into trouble, but I don't have the best grasp of ...
49
votes
3answers
20k views
Why Are Ethernet/RJ45 Sockets Magnetically Coupled?
As the title says really, why do ethernet sockets need to be mag-coupled? I have a basic understanding of electronics, but mostly, I can't figure out the right search terms to google this properly.
49
votes
4answers
76k views
Why are there 3 pins on some batteries?
Lots of new batteries (for mobile devices, MP3 players, etc) have connectors with 3 pins.
I would like to know what is the purpose of this and how should I use these three pins?
They are usually ...
49
votes
3answers
4k views
Why are there only four passive elements?
I've read that there are four types of passive elements: resistances, capacitors, inductors and memristors.
The memristor was predicted 30 years before it was produced. But why couldn't you invent ...
