Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

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1500 questions
41
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2 answers

What did the manufacturer mean by asking if an angle should be made for the fingers?

I sent in Gerber files designed by someone else to PCBWay. It's a cartridge for a Commodore 64. They responded today with this question, and I'm not 100% sure what they are asking. Ref attached screenshot, please advise if we should do 30° degree…
Oggie
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Have microcontrollers replaced simpler ICs?

Is it still worthwhile to learn, for example, how to tune a 555 timer with resistors and capacitors, when you can write a timer program for a microcontroller in a human-readable programming language? Or, to put it another way, are there problems…
user955
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7 answers

Why can't I light a LED with a 1.5 V battery?

The LED I am using requires a higher voltage to light than I have supplied, and as a result, it doesn't light at all. I would expect at least a dim light, but light is not generated. Why this behavior of "if there isn't the required voltage level…
Diego Alves
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41
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12 answers

Doesn't using resistors serial to LEDs all the time waste a lot of energy?

I was wondering for a long time why in schemes which use LEDs for lighting it's very common to put a resistor to go with the LED, and finally it seems like the answer in this question explains why. (It's the easiest way to control the current…
Cray
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41
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6 answers

Why don't we use GaN transistors everywhere?

There has been a lot of research around GaN transistors, proving that they have a very low on-resistance, low gate-charge and are very effective at high temperatures. So why are we still mostly producing Si transistors? Even if the GaN transistor is…
Casper Vranken
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41
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10 answers

Why is the temperature range of industrial and military products so high?

From Wikipedia the common temperature range for electrical components is: Commercial: 0 to 70 °C Industrial: -40 to 85 °C Military: -55 to 125 °C I can understand the lower part (-40°C and -55°C) as these temperatures do exist in cold countries like…
ElectronS
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3 answers

Creepage distance for PCBs handling line voltage AC?

What is the required creepage (e.g. trace-to-trace) distance for PCBs handling 240VAC rms? What about 120VAC? This is for UL and CE certification. The standards for PCB Creepage (e.g. the distance across the surface of a PCB between high-voltage…
Connor Wolf
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7 answers

Is there any reasoning behind component names?

All the components I own have strange names, like a transistor called 2N2222 and a motor driver called L293D. When you see these kind of things writen down do you instantly know what it means or do you have to google it every time? How much…
Buh Buh
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41
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7 answers

Readable and educational implementations of a CPU in a HDL

Can you recommend a readable and educational implementation of a CPU in VHDL or Verilog? Preferably something well documented. P.S. I know I can look at opencores, but I'm specifically interested in stuff people have actually looked at and found…
Eli Bendersky
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10 answers

SPI or I2C: which to use for a longish bus

I'm contemplating a project that would require several AVRs talking to each other over a bus. They'd be separated by as much as 6 feet. It seems like both I2C and SPI can let a series of micros communicate over a bus, but I haven't seen anything…
edebill
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41
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9 answers

How can "purely" electrical circuits emit sound?

Moving membranes or piezoelectric materials obviously produce sound waves, but how can "purely" electrical circuits such as transformers or DCDC choppers (and others) often have an audible noise? Is the material microscopically expanding and…
Mister Mystère
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41
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5 answers

Poles and Zeros in English

Can someone explain, or provide a good reference to an explanation of Poles and Zeros for say, a power supply compensator, or any control system for that matter. I'm not really looking for a mathematical explanation, as that seems rather straight…
bt2
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41
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10 answers

What is a Charge?

I'm a high school student. I love computers and electronics. Few weeks ago, I thought to build my own electronic gadget but, unfortunately I had not much knowledge in electronics. So, I decided to learn. After Googling here and there, I came across…
seek_learn_joy
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40
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2 answers

Purpose of the diode and capacitor in this motor circuit

I'm hooking up a small DC motor to an arduino using an NPN transistor using the following diagrams I found online: The circuit works, and I'm successfully able to make the motor run. Now, I'm seeking to understand why it works the way it does. …
Paul
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2 answers

Why do some pins have `~` signs next to their numbers?

I was looking at my Arduino Uno and I noticed that symbol by digital pins 11, 10, 9, 6, 5, and 3. What do these mean? Does this affect the way it works? Can I not use these pins for certain situations?
Anonymous Penguin
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