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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Is is safe to deal with wiring after only shutting off the room's fuse, but not the main switch? [migrated]

I think the question title says it all: Given a distribution board in the house (220 VAC), is it enough to shut off only the room's fuses, or must one shut off the main switch for the board before ...
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2answers
214 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
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2answers
107 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
52 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
40 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
111 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
157 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 ...
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2answers
190 views

Connecting LEDs to 220v without using a power supply

I'm designing a backlit custom picture frame, and I want to include the power supply (or the lack of one) inside the body of the frame. The problem is, since the frame design is more or less thin, I ...
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1answer
121 views

how to protect a 12 volt operating DC LED Bulb from 230 volts mains supply

I have made a DC Led BULB (7 watt) which is working on 12 volts input. By the way its input voltage range is 12-48 volts DC (using BP 1601 regulator ic) Now problem is that when i gave some bulbs to ...
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1answer
77 views

Building a wall-wart style case

I'm working on a project that will plug directly into the wall outlet, similar to a night-light or a wall-wart power supply. Internally, I'll use a AC-DC converter like this one. It has built-in ...
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0answers
40 views

Voltage at some point on a transmission line (a power distribution line in this case)

I am interested in knowing the instantaneous DC voltage (ball park) at a capacitor bank on a power distribution line at the instant I interrupt the circuit some distance away. If I interrupt the ...
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2answers
69 views

Using DPST Relay to control AC Load

Below is the functional schematic that I am planning to use to control an AC load (air conditioner in this example with max current draw of 32A). Since I am still relatively new to mains power and ...
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1answer
47 views

Mains into a relay?

Will hot/live go into NO and neutral into COM, to switch over 200v? Can someone explain please. I saw in some places it says natural into NO but what into com?
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0answers
70 views

How to control a bulb operating on 230v using a switch operated at 5v

Hello Electrical engineering community, Maybe this is an easy question to answer but I am new to this so definitely need assistance. I want to control a bulb which is driven via 230v AC mains using ...
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1answer
92 views

High voltage distribution line fault current

On a conventional 7,200 volt distribution line, what would be the average fault current in a scenario like the one shown in the video below? Video Specifically, I'm wondering what the power ...
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2answers
84 views

Electrical measurements of Chicago substation from where can I get it? [closed]

I am doing a project on electrical load prediction using machine learning. Machine learning involves creating models based on past data. For creating these models where can I get data regarding ...
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2answers
119 views

Does unplugging a television from the wall socket make it safer? [closed]

Does unplugging a television from the wall socket make the electronic safer (against power surge for example) compared to: Plugged in, button on wall socket is off Plugged in, button on wall socket ...
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1answer
82 views

Strategies for powering an ATtiny micro controller and 40W peltier from mains

I'm trying to power an ATtiny1634 at 5VDC and a 50W peltier element at 12VDC. The microcontroller will, amongst other things, turn on the peltier via a 5VDC non-latching relay. I want to use an ...
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2answers
69 views

Limiting mains current

What would be the best way to limit mains (240V @ 50Hz) current? I want at least 1A of current. The output should be AC 240V at any frequency greater than or equal to 50Hz. It should be able to endure ...
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2answers
137 views

Energy harvesting from AC wire

I'm designing a home automation module and finding a way to supply power. Is it possible to harvest energy from existing AC wire using step-up current transformer? Also I can only find step-down ...
4
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3answers
207 views

What causes old power supplies to start humming?

I have a number of mains-powered devices that have begun humming (I assume at 50Hz, though I haven't measured it). These include clock radios, a speaker system, a lamp (20W halogen with a transformer ...
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2answers
89 views

Solar inverter with mains backup [closed]

I'm looking for a way to partially power an applicance (a fridge freezer for argument's sake) using solar/renewable energy. I don't expect the couple of hundred watts of solar power to be sufficient ...
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1answer
54 views

What will happen if i connect a bulb across 2 AC sources of different voltage [closed]

I was just trying to decode whats happening in my house wiring I have a Fault line indicator bulb for each phase,Sorry i dont know How its connected or anything ... Recently i installed Home ups And ...
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6answers
2k views

What makes mains voltage safe in homes?

When I started learning about electrical engineering, one of the most important safety guidelines that I learned was that voltages over 36V can be dangerous. As my circuits professor put it, 120VAC ...
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0answers
26 views

OrCAD- Hierarchical Blocks - Printing issue

I am facing one issue in OrCAD 16.7 version. Please give your ideas to solve this. Here is my issue. I have created my design using hierarchical blocks. I created one Main page for the whole design. ...
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131 views

Low-pass filtering a 120 volt AC line to remove noise

I have active monitors (speakers) plugged into a 120 V line and they are picking up 120 Hz noise being generated by the TRIACs of the Lutron light dimmers in my house. The dimmers are on different ...
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1answer
97 views

Design steps for a choke inductor

I want to filter out high frequency noise on my power line. At first, I was considering to use an LC filter on the line; but then, I learned about choke filters are used exactly for this purpose. ...
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1answer
129 views

What are the bare minimum parts needed to operate a magnetron?

I recently took apart a microwave, and I managed to get a magnetron out of it, as well as a transformer that appears to be the power source for the magnetron, but looks a little small for the ...
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1answer
83 views

Does coil require extra resistor before connecting mains?

I am planning to build diaphragm air pump. For this instead of using an AC motor, I am planning to connect an aluminium rod to diaphragm, and put a permanent magnet on it that will be pulled and ...
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2answers
85 views

Where can I learn to safely deal with mains electricity? [closed]

I want to start working on projects that directly interface with the mains in my house. I know this is dangerous. I don't want to design something that will fail in a year and burn down my house. We ...
4
votes
2answers
110 views

Safety concerns over generic switching power supply units

I'm looking for a more stable power supply for my 3d printer. I've recently come across the following kinds of switching power supplies. They seem to come in all sorts of different sizes and ...
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0answers
54 views

What controller for a 400W AC-DC SMPS?

I would like to build a big AC-DC SMPS. I built a little one based on ST's VIPer22A. This is a nice little IC that can give up to a couple watts (my design was 5V 1A). It was easy enough to design ...
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3answers
959 views

Why is there a potential difference between neutral and ground (earth)?

I was surprised to find that bridging neutral and ground in a socket at home tripped the RCD. Measuring with a multimeter, there is indeed 0.1 V between them. If the RCD trips at 30mA that would mean ...
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3answers
170 views

SMPS gives “electric shock”

I built the following circuit, a reference VIPer22A circuit. It works fine but I have a little problem. It gives an electric shock on the secondary side. It's not a "line" shock (sticking your ...
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3answers
722 views

What are some problems with running a heating element in PWM mode?

I want to be able to control a heating element's (which runs on 230V mains) power level, and I'm thinking of running it using a solid state relay and PWM. However, I'm unsure of the implications of ...
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2answers
176 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. ...
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2answers
142 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
votes
3answers
109 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
138 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: ...
2
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3answers
338 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 ...
2
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1answer
123 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
108 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
836 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
122 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
78 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
75 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
109 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
49 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
215 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
63 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 ...