Mains electricity, typically a higher voltage AC waveform used to deliver electrical power to households. In North America 120V, 60Hz, in most European countries 230V, 50Hz. What most people will plug appliances into.

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102 views

earth as a voltage reference

Why is the neutral point of the alternator hooked up to the earth which makes all the voltages of the lines with reference to the earth. Doesn't this makes us more risky to the shocks? I think we use ...
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0answers
15 views

If the outdoor MCCB 100 A , can I install the main CB in MDB 150 [migrated]

i have villa , building size is 375 m^2 on the boundary wall of the villa i have molded case circuit breaker (mccb) rated 100 a . I need to install main distribution panel (mdp) inside the villa my ...
2
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2answers
59 views

Mixing two or more AC sources to handle overload

Can I mix two or more AC sources to handle overload and maintain a stable voltage of 230V AC? For example if power from solar panel cannot handle a heavy load can I mix power from different source ...
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3answers
69 views

Fast 220v AC power failure detection

I'm building an AC-Detection circuit. I want to detect when the AC power has failed ASAP so that I can react very quickly. (like 1-3ms should be enough time) This was my first idea. It works in ...
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1answer
32 views

How is this ELCB connected to earth?

I have bought an ELCB and a mini DB board for a small solar/inverter project. My understanding is that an ELCB trips when there is a potential difference between earth and neutral. The diagrams I've ...
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3answers
486 views

Is the design decision for different frequencies in PAL and NTSC related to the AC mains power frequency?

In discussion a friend mentioned: In the original implementation of PAL and NTSC they used the AC current as a means providing the frequency for the TV. As the different mains had different ...
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2answers
70 views

will i damage this toy motor by running it on a higher voltage? [closed]

I have a hand held shaver that is chargeable. the socket plug for the device says 02A250V- and the green battery inside the device looks like this: and the ...
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2answers
84 views

How much ground current vs. neutral wire current?

This is a follow-on question to an earlier question of mine; I think it deserves its own question, though. I am trying to learn as much as I can about how current in a power grid (transmission and ...
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2answers
76 views

Understanding ground current

I am trying to understand ground current in a power distribution system. The basics, of course, are simple: in the power grid, the "hot" wires carry high voltage, while the return path (the neutral ...
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0answers
23 views

Type M AC Adapter Pins -Identification Help

Below is the picture from a Belkin Wemo wireless switch teardown for the side that plugs into the wall outlet. The complete teardown is here They have mounted the AC pluggable pins directly on the ...
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0answers
33 views

Correctly Using ACS712 hooked to a microcontroller

I am making a project that involves AC current measurement from the Mains. I have done a bit of research and have found that the ACS712 can do this. I would like to know the correct way of using ...
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2answers
79 views

Power demand beyond maximum deliverable power

simulate this circuit – Schematic created using CircuitLab We got an elementary dc power system as shown in the figure. The maximum transferable power P_max is 0.5W. Is it possible to ...
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2answers
69 views

Simple surge protection circuit for incandescent bulbs

A friend of mine is having a large, fancy / artistic lamp at home (Europe) and uses a "500W incandescent bulbs on 230V" as recommended by the manufacturer (link). His problem : every month or so the ...
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1answer
48 views

cheap usb hubs passing on mains voltages

So we've heard a lot of sensational stories about people dying from cheap mains->5V USB converters. What sort of corners do these manufacturers cut and do they even save much money than if they made a ...
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1answer
61 views

What is the purpose of an inductor on an incoming AC line?

I am trying to build the following schematic. It is a AC/DC converter from Cui link I do not understand the function of L2. What is its purpose? I am having a ...
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2answers
71 views

Oscilloscope Output with its positive terminal touching human's body and negative terminal left open

it once happened that when I touched the positive terminal of the Oscilloscope input probes letting its negative terminal open, I observed sinusoidal voltage signals with 0.5V peak to peak and of ...
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1answer
103 views

Wired vs SMD resistor on 230V optocoupler input

For circuits similar to the one below, we used large wire resistors with proper power rating in our past designs. The question came up, if it would be a good idea to replace the resistor with SMD ...
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2answers
72 views

resistive braking for induction motor?

It occurred to me that since single-phase AC induction motors can act as generators, it might be possible to brake an induction motor with a resistive load. The basic idea is that when you want to ...
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2answers
94 views

Looking for a simple way to inject a signal on 60Hz Mains line

Okay, so I'd like to be able to inject a really simple signal on top of the 60Hz AC Mains. It doesn't have to contain any data per se, just a simple signal to trigger a receiver on the same ...
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2answers
80 views

Mains isolation is mandatory for UL/CE/CSA compliance and other certification?

I have a design with a non user accesible low voltage section. Is mandatory to do mains isolation to pass succesfully UL/CE/CSA despite my low voltage section is not accesible for user?
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2answers
79 views

Arduino Dimmer Shield Schematics Interpretation

I've read so much about Thyristors, Triacs and Rectifiers on the last days that I'm almost understanding my schematic, but I'm not there yet - I need some help. Overview: I'm making a home automation ...
2
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2answers
125 views

Question on Mains return current

Since the neutral wire is grounded at the circuit breaker panel, I am confused as to whether current actually flows along the neutral back to the service head? If not, then what actually absorbs the ...
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2answers
74 views

unexpected power supply behavior

I am using this large 24V power brick (rated for 9.2A) to power a small circuit (an arduino controlling some RGB LED strip, drawing less than 0.5A). If I physically pull the plug out of the wall, the ...
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2answers
81 views

Differentiate between mains and a generator

This question is related to: Can I differentiate between a UPS, Generator and Main sine wave using a micro-controller? I'm only interested in the difference between mains and the generator. ...
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0answers
30 views

What's the typical harmonic distortion on the secondary side of a distribution substation?

What's the typical harmonic distortion and waveform found at the low-voltage side of an urban substation (I.e: the aggregate of appliances and secondary distribution system impedance)?. If you can ...
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2answers
72 views

DIY Isolated Power Strip?

Would it not be ok / safe to take a surge protector style power strip, cut the mains cable in the middle (or maybe slice it open and just fish out the load and neutral wires so that the ground wire is ...
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2answers
161 views

Need circuit to Switch 240v a.c. mains with 3v or 5v

I have the IRFP460 power transistor which if I understand correctly can switch 20A/500V on 20v input. I am wondering what a circuit design would look like that would allow me to either (a) switch ...
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2answers
109 views

Plugging in an oscilloscope in a land of non-grounded outlets

Background: I have only one outlet in my house that remotely approximates a proper equipment grounding conductor (it's bonded to the mains ground point via the armor of 50s vintage AC, which is better ...
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3answers
140 views

Resistor calculation

I'm still new to electronics and I am trying to do a calculation. Say I have a 100 Watt bulb that runs at 120V and my source is 240V. I know the bulb will blow but my question is: if I wanted to put a ...
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2answers
579 views

Multimeter into wall sockets

If you placed one of the multimeter's probes into the hot slot of the wall outlet and touched the other probe to your skin while grounded, for example to some dirt outside, would you get bitten by the ...
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8answers
980 views

Why are we not always isolating the mains supply?

Something struck me: to protect people, the neutral of the supply is connected on the supplier side to Earth, so that leakage through ground is detected when for example someone touches the phase ...
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2answers
220 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 ...
6
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2answers
160 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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3answers
128 views

Is the white wire carrying any electrons

I don't understand why neutral in 110v , does it carry any current ,does the load like the light reduce the current
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1answer
114 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: ...
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0answers
36 views

Fan needs full power to spin up; would then like to have to run off a speed control

Fan in question: http://www.amazon.com/Active-Air-inch-In-Line-Fan/dp/B002JQ4N92 Fan speed control: http://www.amazon.com/Lutron-DVWFSQ-FH-WH-Single-Pole-3-Way-Control/dp/B000MAVHTG The lowest ...
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2answers
65 views

Is it safe to connect battery in series with wall adapter?

Is it safe to connect a battery in series to wall via adapter? I have an AC adapter which gives me 10 vDC from the wall (220 volts). I've measured the adapter and it outputs 10 vDC. I have a 3 volt ...
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2answers
94 views

Can I power a 230VAC fan with 220VAC?

Here's the fan I want to use: http://www.nmbtc.com/pdf/acfans/4715ms.pdf The 220VAC model costs $70 while the 230VAC model costs $17. Can I safely use the 230VAC model in China, where the mains ...
3
votes
1answer
61 views

Making conducted EMI measurements in the presence of building-wide ground-fault protection for personnel?

As is documented here among other places, the Line Impedance Stabilization Networks used to make measurements of conducted EMI as per CISPR 22, FCC Part 15, and suchnot contain large line-to-ground ...
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4answers
143 views

Providing house wall switches with 3.3v/5V supply?

It's a bit non-technical, but I'd love to hear the opinions of the pros. I'm trying to figure out what is the best way to connect my home's wall switches (lights, etc.) to 3.3V/5V. The plan is the ...
3
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2answers
461 views

How can a light dimmer in series modulate a load?

Not after a full breakdown of how this specific light dimmer works, but rather how a device in series can control a load. A light dimmer has the following wiring diagram. As you can see, the light ...
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0answers
91 views

Inverter using battery even when mains power supply is on [closed]

All the points connected to the inverter are using battery power even when mains power supply is on. When inverter is turned off , those points connected with the inverter have no power, not even ...
0
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2answers
73 views

A relay for each terminal (live and neutral)

I'm investigating a control circuit that switches a heating element. From what I can see there is a relay on both the neutral and live to the heater. The relays are controlled together and cannot ...
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0answers
106 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 ...
2
votes
2answers
360 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, ...
3
votes
2answers
140 views

Are IC sockets suitable for mains voltage?

I need to derive a low-voltage galvanically isolated 50 Hz signal from 230 V mains. I'll use an opto-isolator for this. I'd like to use IC sockets for all ICs in this personal one-off project. ...
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0answers
62 views

X-rated capacitors in parallel

I want to build a transformer-less power supply (capacitive) to drive few 0.5W power LEDs from mains supply (230V). The 1uf X-rated capacitors I have are not good enough to drive them to full ...
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1answer
50 views

What's the purpose of adding a parallel impedance to a relay circuit?

This is the relay section of a PIR Sensor I have taken apart.: L_FUSED is 240VAC, and the relay is intended to turn on a light bulb from "OUT" (standard edison screw), so it could be incandescent, ...
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4answers
174 views

How to control power to a water heater

My water heater element is rated at 3.6kW at 240V. To use solar power efficiently, I would like to use excess solar power (in a grid-tied arrangement) to heat our domestic hot water. Our electricity ...
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4answers
190 views

230 and 240 transformer leads

So I have a transformer that is like 230 || 30 V. One thing I don't get that on primary side it has the following leads: 0 --- 230V --- 240V When it can be useful? I mean I can't think of situation ...