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.

learn more… | top users | synonyms (2)

2
votes
3answers
115 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 ...
1
vote
2answers
532 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 ...
6
votes
8answers
892 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 ...
4
votes
2answers
187 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
votes
2answers
128 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 ...
0
votes
3answers
107 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
1
vote
1answer
78 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: ...
0
votes
0answers
21 views

Power DC motors via UK mains, controlled by arduino [migrated]

So I was wondering if someone could tell me of a method by which I can power a group of 12 motors via UK mains, I assume resistors or something will be needed to reduce the voltage down to that which ...
1
vote
0answers
26 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 ...
0
votes
2answers
57 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 ...
0
votes
2answers
72 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
44 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 ...
0
votes
4answers
108 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
votes
2answers
436 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 ...
1
vote
0answers
48 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
votes
2answers
46 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 ...
0
votes
0answers
76 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
248 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
121 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. ...
0
votes
0answers
55 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 ...
0
votes
1answer
44 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, ...
2
votes
4answers
129 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 ...
1
vote
4answers
170 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 ...
1
vote
2answers
251 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 ...
0
votes
2answers
240 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 ...
2
votes
1answer
86 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 ...
0
votes
0answers
43 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 ...
0
votes
2answers
91 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 ...
0
votes
1answer
49 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?
0
votes
0answers
98 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 ...
0
votes
1answer
103 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 ...
-1
votes
2answers
85 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 ...
0
votes
2answers
149 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 ...
0
votes
1answer
107 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 ...
0
votes
2answers
76 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 ...
0
votes
2answers
172 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
votes
3answers
270 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 ...
0
votes
2answers
106 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 ...
-3
votes
1answer
68 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 ...
10
votes
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 ...
0
votes
0answers
27 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. ...
0
votes
0answers
189 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 ...
0
votes
1answer
205 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. ...
3
votes
1answer
143 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 ...
0
votes
1answer
86 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 ...
1
vote
2answers
86 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
131 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 ...
0
votes
0answers
64 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 ...
2
votes
3answers
1k 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 ...
2
votes
3answers
200 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 ...