Mains electricity, typically a higher voltage AC waveform used to deliver electrical power to households. In North America 120 V, 60Hz, in Europe 220, 50 Hz. What most people will plug appliances into.

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14 views

Wiring GU10 Sockets: Cables are of same color - which one should be “live”? [migrated]

Question: How can I know which cable should be "live" and which one should be "neutral", or does it not matter? (GU10 socket).
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11 views

Should a heavy duty transformer (used predominantly for LED lights) be on the mains ring or the lighting circuit? [migrated]

I am putting RGB LED strip lights in a room, powered by a fairly heavy duty (30A) 12V transformer. The transformer will also power a Raspberry Pi (volatage will be split to give it 5V)that will be ...
1
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2answers
66 views

Detecting Zero Crossing of Mains (Sine and Square Wave)

I need to design a circuit that can measure and output pulses for a MCU at zero crossing of 220VAC waveforms. The application requires that that both square wave waveforms and sine-waves should work. ...
2
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2answers
109 views

Check my math: Calculating the size of extension cord needed

I think I've done this right, but I don't trust myself. Will you check my math and see if I'm right about this, or correct my error if I'm wrong? The facts I have a device (A Yamaha Stagepas 400i ...
2
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3answers
96 views

What is the easiest way to identify what leg of a 220V panel a 110v outlet is on?

I need to connect two devices on the same leg so they can communicate. Basically I am trying to send my internet to my remote garage over the power line. I need to have them both on the same leg in ...
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1answer
113 views

How can I make a POWER-LED Lamp?

What is the best way to light 10 POWER-LEDs with AC mains (220V)? (I want to make an LED lamp.) Here is more info: I have 10 of these POWER-LEDs: Product Chip: 40x40 mil Chip Brand: ...
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3answers
198 views

Tapping energy from high voltage AC transmission lines

The details are hazy as I recollect this from my nipper days.Many, many years ago. “Persons were charged with stealing electricity by placing a large coil, somehow, near high voltage AC transmission ...
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1answer
102 views

5V Power Supply oscillates once another consumer is turned on

I live in Europe and we have 230V coming out of the power outlet. I have several consumers on one outlet: 5V DC supplies for Router, HDMI-Switch, Ambilight, one Computer, one Macbook and a fan). The ...
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0answers
75 views

How can this isolated DC/DC converter claim a 3kv rating?

I'm referring to the Murata Power Solutions CME series DC/DC converters. Datasheet: http://www.murata-ps.com/data/power/ncl/kdc_cme.pdf If you look at the footprint of package (the -3C variant), ...
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3answers
370 views

Aren't non-polarized plugs a little dangerous? Why still use them?

Sorry if there is an answer for this kind of question somewhere. I can't find it anywhere. Take a look at obvious toaster example: If you live in Europe and have non-polarized plug and a toaster (a ...
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1answer
53 views

Connecting common of relay with main cable of 240VAC

I trying to control my turntable switch with Arduino. This is a toggle switch with 3 wires one wire is for CW rotation the other one is for CCW and the other cable is main with 240VAC. I am using this ...
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0answers
55 views

How to use LM56 to switch on/off a 2kW heater using a MOSFET

I have an oil heater at 220V/2000W so lets say 10A (maybe more when it starts?!). I was thinking of creating a circuit to switch the oil heater on/off with a LM56. Is it possible using a MOSFET ...
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1answer
36 views

How to use LM56 to switch on/off a 2kW heater

I have an oil heater at 220V/2000W so lets say 10A. I was thinking of creating a circuit to switch the oil heater on/off with a LM56 (http://www.ti.com/product/lm56). Is it possible using a relay or ...
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1answer
101 views

How is line voltage measured?

When people say that the line voltage in the US is 120 volts, do they mean amplitude, Vpp or Vrms?
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1answer
36 views

12 v xbox connection [duplicate]

Hi again if I just want to connect my tv and x box360 to the mains I've got it connected to the van at no so the neg is to the body and pos is by the fuse box. Can I just wire the transformer neg to ...
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3answers
96 views

How does a “break” in the neutral wire enable it to reach the full line voltage?

The answer to Is the neutral wire considered safe? states: When everything is working correctly, it should be at most a few volts from ground. However, and this is the big gotcha, if there is a ...
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2answers
55 views

Is it possible for mains power to drop during peak times?

Disclaimer: I'm not after repair information or modifying any appliances myself. I'm after a reason why this is happening. I have noticed that during peak times (6pm - 10pm) that power to mains ...
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1answer
90 views

Why does a mains appliance give a shock after it is completely unplugged

My wife has a food processor, bought a few weeks ago, powered directly from the A.C. mains, i.e. not via a "wall wart" power supply, and, after it has been switched off at the wall and fully ...
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0answers
44 views

Determine a transformer's windings

I'm trying to find out what the pinout of a transformer is. I found the following diagram in a service manual of a device similar to what i salvaged this transformer from: Now. To test this, I'm ...
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1answer
60 views

I want to adapt a VFD

If I feed single phase electricity into a 3 phase input VFD, I know it needs to be derated on the output by about 50%, but how does it cope with the difference in voltage, as rectified 230v rms gives ...
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1answer
124 views

Where does 264Vac come from?

Power supplies often accept an input range of 90-264Vac. I am wondering where the 264 comes from. A couple of random examples from power supplies available: 85 - 264 Vac input range (100 - 240 Vac ...
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4answers
436 views

How can a faulty USB charger kill you?

This question relates to this incident here. Where a women in Australia died from a faulty USB charger that allowed the full 240v mains voltage through the USB cable. Now from my understanding you ...
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1answer
97 views

Is a 115V rated transformer expected to accept US mains voltage (120V)?

< question completely reworded since people thought I was looking for appliance repair instructions > Many "Power Transformers" are rated at 115V or 230V. It seems to be the most popular rating. ...
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3answers
205 views

How to build very low cost current transformer?

Im building low cost home energy monitoring system. I want to see how much energy is used by water heater, big water pump, kitchen equipment, lightning, computer. I would be awesome if I could measure ...
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3answers
392 views

Transmission lines in USA, household transformers - efficiency and economy

I want to ask about efficiency and economy of electric power distribution in USA. I live in Europe and American standards are so weird for me. I was very surprised when I saw this: See inside main ...
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1answer
394 views

How can I safely prototype a mains power circuit?

I'm building a device that has a mains power component, which I need to prototype before building to make sure everything works. I know I need to make sure wiring—and insulation!—is thick enough to ...
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0answers
46 views

How to add a desirable phase shift in the input from 3-phase ac mains?

I want to build a 12 pulse rectifier circuit. I know delta-wye or wye-delta transformers can be used to add phase shifts equal to the multiples of 30, but I don't want to use transformers. Is there ...
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2answers
110 views

How can I make a 5mm LED rope using 6v transformer [closed]

I want to glow LED using a 6v AC transformer. I want to add 18 color changing leds (5mm) as series. I cant add too many wires through the rope (pipe). See my plan: what are the components I ...
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1answer
114 views

How can I make a LED rope using mains (AC power) [closed]

I want to glow LED using AC power. How can I add combine multiple LEDs to make an LED rope? Versions that I would like to build are: 18 x 5mm LEDs 20 x 10mm LEDs Mains voltage here is 220 V AC ...
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1answer
108 views

How can I make AC powered 5mm LED string? (with more than 16 LEDs) [closed]

I want to make an AC powered 5mm LED string. I searched a lot but I never found a working one. I just tried one experiment from the Instructables site. But when I connected it to AC power, one ...
2
votes
2answers
108 views

3-way dimmer switch schematic

I am building an AC dimmer circuit to control from an Arduino using this schematic: I need to make this dimmer so that it can be used as a three way switch as well. How would I modify this circuit ...
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2answers
266 views

Is a 250V lamp compatible with both 120VAC and 220VAC?

Is a 250V and 660W lamp compatible with both: 120VAC at 60Hz, and 220VAC at 50Hz? And why? Also, does the frequency of the mains have any bearing on the lamp? In North America I was very ...
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2answers
88 views

Replacing a battery pack with a mismatched DC source

I have a PCB which is nominally powered by a custom battery pack. Specifically, this battery pack: So five cells connected in series, at 3.6V each, which I assume means that the nominal output ...
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1answer
52 views

Would this be ok to control the speed of a PC fan? [closed]

I have a 240mm PC fan connected to a 12v adapter. The fan is quite noisy and i would like to have the option to turn the speed up/down or off completely. The Fan is: Current (A): 0.18 The 12v Mains ...
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1answer
52 views

Current clamp mains appliance [closed]

I want to measure the current to a device using a current camp. I have a mains extension cable I plug the device in and I strip the mains extension cable to reveal the live, neutral and ground wires. ...
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4answers
2k views

Where is the ground/negative for overhead power lines?

I recently learnt that ground can be used to complete circuits using high voltages. I'd like to know if this is how overhead powerlines work, and if so where exactly do the cables/circuit terminate - ...
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1answer
168 views

Small AC Transformer

Came across these small Zwave controllers here .These are small enough to fit inside the electrical switch housing in the wall. Just wondering how is this device so small as the AC->DC transformer is ...
5
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2answers
328 views

It is it possible to safely use a 110V variac (variable transformer) at 230V?

I've come across a variable transformer/variac which is designed to be used with 110V input. Our line supply here is 230V. If I was careful not to exceed the VA rating of the transformer (920VA) ...
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4answers
262 views

Surface mount transformerless 230v to 3.3v on a small board

I am trying to design a 3.3V mains power supply to go on a PCB approximately 50x25mm in size (this will include other functions too!). I've come across the Supertex SR086, which is almost perfect, ...
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2answers
111 views

How to connect 120V to a relay on a prototype board?

I'm designing a microcontroller controlled switch. I idea is to have a 120V outlet controlled by time of day, or a motion sensor, etc. The plan is to have a lamp plugged into the outlet. I will ...
1
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1answer
106 views

How do external circuits in light switching units (such as Lightwave RF) use the mains wiring for power?

LightwaveRF is a simple switching unit that contains additional circuitry to enable automatic wireless switching. The additional circuit is powered by the mains light switching circuit. This is my ...
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1answer
85 views

Safety considerations designing a mains powered device

I am building a device for hobby purposes- a 3D printer specifically. It already uses mains (240V AC) powered heater elements to heat the build chamber (4 ceramic cartridge elements at 100W each). ...
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1answer
52 views

AC Transformer Power Cable

I have recently purchases an 120 Vac to 12 Vac transformer similar in design to the one shown here. I am curious as to the best way to wire this up. I am not a big fan of making a suicide cable for ...
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3answers
139 views

High frequency mains sensing

I want to sense mains voltage at a frequency faster than 5000Hz, with a microcontroller. The idea behind this is to visualize the actual shape of the AC voltage, and eventually to compare it with the ...
0
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1answer
77 views

Strange voltages in my office space [closed]

On wanting to put on lamps I measured the conductors coming out of the ceiling - and they seemed a little off to me, so I wondered if anyone could tell me what it means. I'm in Germany, and the ...
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2answers
137 views

Fault-current circuit breaker breaking on grounding neutral conductor?

I just put some lamps on and got the fault-current circuit breaker triggered. While skinning the earth conductor the knife touched the neutral. I was a bit puzzled: I thought that happens only under ...
5
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4answers
388 views

Using oscilloscope safely with AC mains

I know there is quite few discussions already on this topic, but since english isn't my first language I though it better to get some more information about this. I have used oscilloscopes to ...
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1answer
716 views

50/60Hz inverter output inductor design

Given a SMPS PWM inverter (for example an UPS) supplying voltage/current at 50/60Hz, how do you design an output inductor? I don't mean how you compute its value in uH/mH nor its current rating in A. ...
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1answer
107 views

Is there any benefit of making lamps with high wattage LEDs but low wattage driver circuits other than cost?

Over the past few years I have bought a number of GU10 mains voltage LED bulbs and have generally been disappointed with their brightness. The 9W LED bulbs I bought (supposedly 460-590 Lumen) produce ...
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0answers
113 views

How to isolate DS2406 switch from mains? [closed]

I would like to use a DS2406 1-wire control chip to switch a mains load. Isolation is required and I would like to use the 1-wire supply. There are no power supply at the remote end, only 1-wire ...