Electrical Engineering Stack Exchange
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1500 questions
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5 answers

Serbia, Kosovo power grid row delays European clocks. Why?

According to this article (and a lot more published today on the same topic), Kosovo electricity net production balance has decreased during the last weeks. This has led to a small deviation of the European network’s frequency (from 50Hz to…
Evariste
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6 answers

Why do many laptops run on 19 volts?

Typically mobile devices that have a mains-powered supply will accept voltage that is multiple of some single battery voltage. For example, 4.5 volts is 1.5 volts (AA primary battery) 3 times and 36 volts is 3.6 volts (Li-Ion battery) 10 times. Now…
sharptooth
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2 answers

When to use what transistor

So there are several types of transistors: BJT JFET MOSFET Combine all that with the various flavors of each (NPN, PNP, enhancement mode, depletion mode, HEXFET, etc) and you've got a wide array of parts, many of which are capable of accomplishing…
Joel B
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72
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7 answers

What are the freeware SPICE simulators available?

Does anyone know of a freeware SPICE / circuit simulator? SPICE (Simulation Program with Integrated Circuit Emphasis) is a general-purpose, open source analog electronic circuit simulator. It is a powerful program that is used in integrated…
Edward
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71
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6 answers

Relation and difference between Fourier, Laplace and Z transforms

I have become a bit confused about these topics. They've all started looking the same to me. They seem to have the same properties such as linearity, shifting and scaling associated with them. I can't seem to put them separately and identify the…
Vineet Kaushik
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71
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3 answers

MOSFET: Why the drain and source are different?

Why the drain the source terminal of the MOSFET function differently while their physical structure is similar/symmetrical ? This is a MOSFET: You can see that the drain and source are similar. So why do I need to connect one of them to VCC and the…
Dor
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11 answers

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? I'm just curious, I don't see how this could be…
coder543
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8 answers

Why aren't FPGAs ubiquitous?

Reading about FPGAs, if I understand correctly, they are basically fully configurable logic gate circuits. Being this, one can design anything with them. One can design everything in the most customized way possible and hence, meet the same ends in…
Utku
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12 answers

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 in advance for your consideration. First, let…
starbucksguy
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8 answers

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 is only a mile away or something). I've asked this…
user2476549
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8 answers

Why do we need an isolation transformer to connect an oscilloscope?

My professor always insists that I provide power to an oscilloscope thorough an isolation transformer. What is the necessity of this? What is the risk if I don't connect it?
noufal
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67
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3 answers

Why is kerosene stopping my red LEDs from illuminating?

I initially posted this on chemistry.stackexchange but didn't get any answers, so I'm reposting it here. Long story short - we have an electronic product that is submerged in fuels (kerosene being one of them) and uses an RGB LED (click here for…
Amr Bekhit
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67
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9 answers

Difference between latch and flip-flop?

What is the difference between a latch and a flip-flop? What I am thinking is that a latch is equivalent to a flip-flop since it is used to store bits and is also equivalent to a register which is also used to store data. But after reading some…
ATR
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67
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8 answers

Why is high input impedance good?

Naive perhaps, but Why is high input impedance a good thing? Is high input impedance always a good thing?
Everyone
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67
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4 answers

What kind of glue should I use for PCB-mounted components to avoid vibrations?

I want to protect the PCB-mounted components from vibrations. What kind of glue/substance should I use? What are the most prone to failure components due to vibrations?
m.Alin
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