Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [ac]

AC stands for Alternating Current. It usually applies to voltages with >100 V RMS, but can also be used for other AC voltages, like 24 V industrial AC power.

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NEMA 5-15P blade holes

Why do most NEMA 5-15P (North America 125V 15A) line and neutral blades have holes in them? I've been wondering this for quite some time and haven't yet found a satisfactory answer.
Adam Lawrence
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Why do we use \$s=j\omega\$ in AC analysis instead of \$s=\sigma+j\omega\$?

In AC analysis, \$s=j\omega\$ when we deal with \$sL\$ or \$1/sC\$. But for a Laplace transform, \$s=\sigma+j\omega\$. Sorry for being ambiguous but I would like to connect the questions below: Why is sigma equal to zero? Is neper frequency…
user23564
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Is a sine wave (or any signal) that has no zero crossing still considered AC?

This question will most likely come down to semantics. A friend and I were discussing a point that his EE instructor made, that if you consider the output from a solar panel over more than a few days, it effectively is a cyclic wave, and thus is AC…
JYelton
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Burnt AC Bulb Failover

I have a 60W, 120 VAC incandecent bulb used as a heater. Today it burned out and resulted in a water system freezing. I would like to be able to hook up a spare bulb that can come on if the first bulb goes out, or some similar system of redundancy.…
Dark Falcon
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Home-built machine: how to make the 110 V AC electrical installation part "by the book"? (safety, "code")

I am building a machine to manufacture optical components. The source of mechanical power is a 1/4 HP motor that's plugged into 110 V AC. Various parts of the machine receive mechanical power via belts and pulleys. The machine is a large square-ish…
Florin Andrei
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What keeps mains power at 60hz?

In a power plant, what keeps the power at a solid 60hz? It seems like turbines can't always be running at the exact same speeds, given that combustion doesn't always give the exact same temperature (my dad works at a waste to energy plant, which is…
Kyle
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High frequency mains transmission

Someone told me that if we used something like 1 kHz AC instead of 50 or 60 Hz AC, it would end up being much cheaper and efficient, because we could use smaller transformers. Is this true? It seems like it would probably cost more as the generators…
Thomas O
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What difference does it make to an appliance whether the supply is sinusoidal, or any other shape?

Just what the title states. I understand some appliance/s may be damaged if the supply is any shape other than sinusoidal. E.g. sawtooth, square ... Why is this the case? How does the shape of the supply signal matter to an appliance?
Everyone
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Are both wires on an AC/AC transformer live?

I am trying to get my head around using (9v) AC on a circuit. As there is no polarity, I cannot use a multimeter (as far as I know) to determine if both are live or whether one is 0v. The transformer I have has a 3.5mm jack and I'm reluctant to cut…
Ryan
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How is the 220V line in US different from other parts of world? Does a US 220V line need two switches for each wire?

Today my A/C compressor had given up its ghost and when I tried to disconnect it from the wall switch after turning OFF the wall circuit-breaker,I assumed like most 110V lines where only one line (Live-L) lights with neon tester. When the circuit…
The_Vintage_Collector
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Phasor to Rectangular Confusion

I'm doing an assignment on circuit analysis with phasors and it's brought up a point of confusion for me on how Phasors convert to rectangular form. My textbook defines phasors as $$v(t) = V_M\text{cos}(\omega t + \phi) = \text{Re}[V_Me^{j(\omega t…
wagboi
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What would happen if you accidentally switched live and neutral?

Short and simple. What would happen if you accidentally switched the live and neutral wires when wiring your home electricity into the distribution board?
bitshift
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How can an intense solar storm harm the power grid?

I have read reports that an intense solar storm can cause Ground Induced Current to damage or disable the power grid. This doesn't make sense to me. The assumption seems to be that transmission lines have a neutral conductor that is earthed at…
psusi
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33V residual AC voltage in domestic circuit when switched off? Neutral switching?

I have searched Google, but get bombarded with "RCD" type answers. I read a few answers here that may have been relevant but turned out not to be, so I post my question. Being my first, I may unintentionally break some rules - hopefully not. I was…
Erg
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If I connected a voltmeter across the source capacitor combination of a RLC AC series circuit, what maximum voltage would it read?

Since phasors sum up vectorially, I believe it is going to read \$ (V²+(V ᶜ)²+2VV^{c}\cosθ)^{\frac{1}{2}}\$, where \$V\$ is the source maximum voltage, \$ V^{c}\$ is the capacitor maximum voltage and \$ \theta \$ is the phase angle of the source's…
Jack
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