This tag refers to alternating current mains power. It usually applies to voltages with >100V RMS, but can also be used for ex. 24V industrial AC power.

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53 views

Why does the original Nintendo take 9V AC instead of 9V DC?

i have found an old Nintendo NES 9V wall adapter which is in fact not an AC DC adapter because it's an AC AC adapter. It's the first time i see an AC adapter that ouputs alternating current, Why did ...
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3answers
43 views

How do I bias an AC signal for sampling?

I want to sample a 10Vp-p 50Hz sinusoidal signal. My ADC can only sample between 0V and 5V, so I need to bias the voltage around 2.5V. I only have a positive 5V power supply. To do this, I was ...
0
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1answer
68 views

Using two Mosfets for AC

Im having trouble getting my head around using two mosfets to pass AC. I have reduced my schematic to its bare bones to help keep it un-cluttered. The aim of this circuit is to use PWM to dim a bulb ...
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2answers
86 views

Sensing AC high voltage to microcontroller

I'd like to sense if I have AC 220V 50HZ available, and convert it to some logical level. I made such circuit, will it work? I use C1 as a resistor. Any recommendations what can be improved?
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1answer
44 views

Multimeter reports voltage but no power?

I have an Insteon FilterLinc, which is an electrical line filter. It doesn't work. When I connect a lamp to the "filtered" outlet, I get no power. So I stuck multimeter probes into the filtered outlet ...
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2answers
56 views

Extending the backup runtime of a UPS with an external car battery

I'm looking for a simple/inexpensive way to have a longer power backup time. My fist thought was putting 2 cheap UPSes in parallel. But I quickly found it's not that simple. You would need another ...
4
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2answers
179 views

If a large AC generator is overloaded, will it lose frequency or voltage?

If a large AC synchronous generator, like one from a hydro dam, were to receive overdemand from the grid, would it start losing frequency or losing voltage? I know they have several safeguards to ...
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1answer
31 views

Recommended electric heating devices for apartment [closed]

Our 2-bedroom apartment has a large living room and regarding heating devices, we only have electric ones. We have the typical AC device which can also work with hot air and baseboard electric ...
6
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2answers
122 views

Turn a mains light on slowly

I've been looking at creating a simple circuit to slowly turn a halogen daylight bulb on over about 30 minutes as soon as power is supplied to simulate dawn. I've got a 240VAC 42W halogen bulb that ...
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0answers
52 views

How can I convert very high, fluctuating, AC voltage to 240VAC at 50Hz?

I'm about to finish a generator-alternator setup which will generate 9-phase AC electricity at (as yet unknown) very high voltage, most likely around 4800V. I'm not sure what the frequency will be, as ...
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3answers
94 views

Can voltages be different if watts are the same? Does DC vs. AC change this?

I'm currently building a home in a van, it's my first tango with electrical engineering. I watched a video on voltages and amps and my understanding is basically like so: a battery is like a water ...
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8answers
2k views

How can a phone wire have multiple frequencies at once?

How can a phone wire have multiple frequencies? In my Networks Textbook about DSL vs Dial Up it says the following: The residential telephone line carries both data and traditional telephone ...
1
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1answer
76 views

Is it possible to connect a UPS in parallel with the mains?

Short version: When a UPS is plugged in to the mains, is it possible to plug the UPS output back to the same mains? Will that work as an emergency power backup for the mains circuit? Longer version: ...
2
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1answer
55 views

Ground impedance monitor circuit design

I'm trying to design a ground impedance monitor. The idea is that the equipment in question needs to disallow operation if the ground wiring is disconnected or the connection is poor quality. This is ...
0
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0answers
46 views

LM8560 not putting out enough power to seven segment display

I have built a digital alarm clock using an LM8560 chip, the chip however does not seem to output much voltage to the display. To solve this problem I had transistors connected to each of the legs of ...
0
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1answer
42 views

Reduce 160 Volts AC to 100 - 110 Volts AC (EL Wire Tape) Help

I am trying to put EL Wire Tape in a project that I am working on. I decided to go and build an inverter for 12VDC to 100VAC and that fell through. I couldn't find any guides that helped on EL Wire ...
0
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1answer
59 views

Will replacing the MOC3024 with MOC3021 make any change

I'm student of 10th grade and new to electronics I'm trying to make a switch to control appliances which runs on AC mains and I don't want to use any relay see the circuit diagram from the link to ...
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1answer
51 views

Why is the complex representation of voltage V*cos(wt + phi) when driven by a sinusoid? Shouldn't a sinusoidal voltage be represented by sin function?

A voltage across a circuit component at time t can be calculated by $$V*sin(\omega t + \phi)$$ however in my book when it introduces complex numbers to represent voltages it states a voltage ...
4
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0answers
2k views

Why DC is not used for long distance voltage transmission? (Tesla vs Edison 2015) [duplicate]

It seems this question has been marked duplicate but I believe the answers given here is much more in detail. Why we are still using AC voltage for long distance voltage transmission. As we know with ...
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1answer
80 views

Converting clock radio from 60 hz to 50 hz

I have an old clock radio that works fine, except for one detail. The clock is made for 60 hz mains but I would like to use it in a country where 50 hz is the standard. As the clock directly relies on ...
0
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1answer
28 views

Timed Selection Between AC Power Sources

I would like to be able to run a freezer from AC power line A in the daytime and AC power line B at night. Right now, I am manually unplugging the freezer from power line A and plugging it into power ...
1
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1answer
31 views

How to determine the minimum proximity of magnet to an AC line for no electrical impedance?

As the title says, I am wanting to calculate the minimum proximity for a magnet to be near a AC line for no electrical impedance. My scenario is this: I have a theoretical device like MagSafe ...
0
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1answer
52 views

multi channel ac dimmer for arduino

I have been looking for a simple ac dimmer circuit to use with my arduino and/or raspberry pi. I have used the TLC 5940 PWM Driver before just to control LEDs and I wanted to adapt this to controlling ...
2
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4answers
167 views

Generating a sine wave over a big frequency range

I want to build a circuit that can generate sine waves at frequencies controlled by a computer or a microcontroller. I would like to go as low as 0.01 Hz (down to 0.05 Hz would probably be acceptable) ...
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2answers
64 views

Power and control 3 phase ac induction motors with dc source

Background So we are making a drive system to be used in a medium sized catamaran. The catamaran will use two water-jets powered by two 3 phase 380v ac induction motors. The entire system will be ...
0
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2answers
79 views

effective voltage of a sine wave

I am looking for effective voltage values for calculating power in a AC sine wave supplied circuit with a resistor under 2 conditions : full wave rectification; half wave rectification. I have ...
2
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1answer
231 views

What could this scammy “magic whole-house electronic powersaving surge protector box” have actually done?

My parents had good intentions, I guess, but the company that sold them this bad boy probably didn't. After blowing a fuse at their place, I noticed this box hooked up to the breaker panel. It was ...
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1answer
98 views

Workings of a microwave oven magnetron transformer

I took apart an old microwave oven just to see what happens with the circuit inside it. The overall idea is actually pretty simple, but I'm having a hard time figuring out some parts of the circuit. ...
2
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3answers
259 views

Do carbon film resistors have any effect on AC?

Carbon film resistors are basically an insulating (probably ceramic) rod covered in a carbon film that is twisted around it, as shown in the picture below: However, this seems very similar with a ...
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0answers
53 views

Could mains electricity produce Lichtenberg figure on human skin?

Could standard mains electricity (50hz 220V AC in my country) in some conditions produce a visible Lichtenberg figure on human skin or anywhere else?
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2answers
72 views

Identify coils end in 3 phase AC induction motor for star-delta configuration

In general if I look at a 3 phase AC motor outlet wires there are six wires that comes out of motor, three of them are marked to show coils end and other three are not marked which show coils other ...
11
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9answers
3k views

Is current with a frequency less than 1 Hz still considered DC?

We had a big argument last night with vague conclusions. Is the current with a frequency less than 1 Hz considered DC? It would still resemble a wave...
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0answers
75 views

Keep volts the same but increase the amps in a 60hz 120v AC circuit

I have a over the range microwave with a built in fan for exhausting range fumes below. Would like to add an inline fan to it in the attic that matches the speed of the fan in the microwave but I ...
0
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0answers
46 views

AC Motor operating region

I've been using an ABB IRB 2400 robotic arm to gain experimental data and write a report based on the data. I found that when I operated it at different speeds for pre-programmed paths, I got a ...
2
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1answer
81 views

Why doesn't the RMS current and voltage give me average power?

Apologies for the multiple bridge rectifier questions. I have a 230V/9V 10VA transformer, and I want to know how much DC current I can draw from this circuit. From this I assume that the ...
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3answers
77 views

Why does the current waveform become non-linear in a bridge rectifier?

This is my bridge rectifier circuit, and I'm trying to understand why the current waveform of the source deforms the way it does when you approach an ideal capacitor. Source V1 is 9VAC. I simulated ...
0
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1answer
97 views

Capacitive transformerless power supply, AC polarity problem

I have implemented a "Capacitive transformerless power supply" to control a microcontroller-based circuit that contains capacitive touch sensors, and I had an "AC polarity problem" Surprisingly, the ...
2
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4answers
113 views

Whats the point in conserving electricity if the AC current produced cannot be stored?

If we cannot save the ac current produced in a battery or some device like the DC current there is no point in conserving it because current once produced should be consumed somehow!! My faculty said ...
1
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1answer
40 views

Capacitance value - AC RC Circuit - Impedance Method

Here is the circuit: simulate this circuit – Schematic created using CircuitLab \$ V_i = \frac{8}{\sqrt 2} \angle0° V\\ V_c = \frac{6}{\sqrt 2} \angle45° V\\ R = 1000\space\Omega \$ ...
0
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1answer
37 views

Forced Response Test Bank Question

I'm trying to calculate the forced response for a current in the above problem. I'm having trouble getting the right answer, and I was hoping someone could take a look and point me in the right ...
1
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1answer
128 views

What are the AC characteristics of a battery?

I'm planning on building a single cell AA NiMH battery charger and in the process I decided that I must also build a battery simulator to help me debug the charger. In my research, the best simulator ...
2
votes
2answers
247 views

Type of switch for AC power cord?

I have a power supply that has only screw terminals for its AC mains input. Currently I'm using a power cord from a computer that I cut the female end off of and attached fork terminals to (live, ...
1
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1answer
43 views

Sinusoids and Phasors AC circuit impedance

Hello. I've been doing problems, and transforming from time domain to phasor domain to find input impedances seems simple enough But I've come across a circuit with a dependent voltage source, as ...
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2answers
43 views

Value of omega from forced response V0

Based on figure. Maybe a simple question, but I'd like to know why that if forced response is zero, then $$\omega L = \frac{1}{\omega C}$$ where \$L\$ is the inductance and \$C\$ is the ...
0
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0answers
66 views

using 2 Arduino Interrupts simultaneously to detect AC phase

I've built an AC power bar that is digitally dimmable using a modified version of this circuit. The modification is that I am using 2 separate AC power lines that would be connected to different ...
0
votes
1answer
105 views

provide 3.7v source to android tablet

Android tablet mostly needed a 3.7V Lion battery to run on it. If I were to replace the battery with a power source, how can I provide such a 3.7V source from some existing products such as 220V/5V or ...
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1answer
42 views

Mesh Analysis on AC circuit

I'm doing a practice problem and I'm unsure how my approach did not receive the same result as the solution. Any help would be appreciated. Below is the Figure along with the solution as well as my ...
2
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1answer
100 views

Power factor correction in a simple phasor circuit

I've been having a bit of trouble with a relatively simple power factor correction problem involving a simple circuit in the frequency domain (\$f=50\,\text{Hz},\omega=2\pi f=100\pi\,\text{rad/s}\$). ...
2
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0answers
81 views

Discrepency with experimental vs. simulation of AC-DC circuit

I'm analysing a PIR Circuit's power supply, but I'm having a large (almost double) discrepancy between simulation/theoretical current values and experimental values (experimental is almost half ...
0
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1answer
60 views

Where do I connect earth wire?

I'm trying to use this delay timer to control an exhaust fan. I have a 3 pin connection (with earthing wire) powering this fan and it works fine. If I have to insert this delay timer module in ...