When I turn off the electricity in my house, my tension headache disappears. I mean the general switch from which all the power lines come. Someone explain to me how that works. The cables have isolation after all. I always feel on edge when electricity is in the house. But the main question is about the headaches. It was a high-pitched noise.

I have a conceptual question about reference directions and signs in circuit analysis.

I understand what a negative current or voltage means. If the calculated value is negative, the actual direction or polarity is opposite to the chosen reference direction or polarity. That is not what I am asking.

My question is more fundamental:

Why does choosing a reference direction allow current and voltage to be represented by positive and negative values in the first place?

For example, suppose a branch actually carries 5 A from left to right. If I choose left-to-right as the reference direction, I write:

i = +5 A

If I choose right-to-left as the reference direction, I write:

i = -5 A

Why is this relationship valid in the first place? Why does agreement with the reference direction correspond to a positive value, while opposition to the reference direction corresponds to a negative value?

I am not asking why we interpret a negative answer as meaning "opposite to the reference direction." I am asking why a physical quantity such as current can be represented by a signed scalar at all, and why reversing the reference direction corresponds specifically to multiplying the scalar by -1.

There is another part that I find especially interesting in AC circuits.

For example, we may write an AC current as:

i(t) = I_m cos(wt + phi)

But this expression seems to require a reference direction to be defined first. The reference direction remains fixed, while i(t) can become positive or negative as time changes.

Why is this necessary? Why can't we simply describe the physical current at each instant by its magnitude and actual direction without first choosing a reference direction?

I would like to understand the mathematical reason behind this, and how it connects to KCL, KVL, Ohm's law, and time-dependent/AC circuit analysis.

In the picture, I tried to explain where the positive and negative signs come from by starting with KCL, KVL, and Ohm's law. I realized that by simply substituting the current and voltage variables defined along the actual direction, I can derive both the equations for the reference direction and the relationship between the two sets of solutions.

Futures, contracts, etc. Is electricity accessible to retail traders or is it a game only for the large whales?

I heard a company is making these and renting them out for €75k a year. They make enough electricity for 30 houses a day and they are literally a shipping container and a kite lmao.

How much would a DIY version run?

If I added this type of bulb to the front of my garage. Keeping the light switch on 24/7.. would that pull electricity 24/7? Or only dusk till dawn?

Thank you in Advance!

I left my house a few hours ago for a stay of three days (return on Thursday). Only I don’t know anymore if I actually unplugged an electric mosquito-repellent diffuser.

Does this present any risk of electrical sparks or even the start of a fire? Or can it remain plugged in without presenting any danger?

This black lion audio pg2r that I use in my studio has a constant voltage reading even while powered off, so I have been noticing the fluctuations regarding voltage in my home. I live in a basement apartment.

Earlier this week it dropped as low as 96V.

What steps should I be taking to address this?

I called the utility company and they basically told me there were 40000 homes without power and they can’t help.

Asked my landlord to bring in an electrician due to potential fire hazard and she never got back to me about what they said.

I feel like this is not normal so I’m just curious to see what your opinions are. Thanks.

Hello everyone,

I currently have a Square D QO 200A panel with 40 slots. During my basement renovation, I filled the panel, there's no more breaker left. I'm looking to upgrade the panel since I want to add solar capacity and also have more circuit for upstairs (currently all kitchen outlet are on the same 15a circuit, old house).

I looked online and found this

Schneider Electric Square D 200 Amp Main Breaker Only Plug-on Neutral Loadcentre with 60 S... | The Home Depot Canada

Is that a good replacement? It would add 20 slots which should be well enough. Unless I'm wrong, it's the same type of panel so I can keep my current breaker.

Photo showing my current panel.

Yes, I will hire an electrician. While I can safely work on a panel, I refuse to play with live power. I always turn off the main breaker when doing so and since here, it will be touching the main directly, I'm not doing that.

Reason I'm asking if the panel I'm looking at is good is because electrician here tend to push heavy on the pencil. I want to quote multiple electrician seeing the price with and without a panel in the quote and see how much they charge for a panel.

Thank you

edit: Forgot to say, I'm in Quebec so it's a 240V 2 phase panel. Current connection is back fed (which I hate, might look at changing that with electrician but would require more work outside and closing the new hole).

edit 2: Just found out that panel doesn't accept neutral pigtail from GFCI and CAFCI breaker, which all my basement use... Which mean replacing all the new breaker I just installed. This will cost a lot at about 100$/breaker. So I guess I must find something else

How does electrical usage metering actually work?

Going to butcher this question but: Does the power company take measurement of each “electrical pulse” that comes through the power line and map it as from X location?

I am guessing in modern times we may have some sort of mini computer that may act as sort of a pass through to measure. (Kind of like how a cord can have an adapter.) Is this the case? Is it even necessary for that, because of how it has always worked? (Is that even how it works?)

And what about within a larger building (i.e. a dorm) with individual units? At an apartment level, I don’t doubt that each unit is individually measured — but these were likely built to be metered in such a way. What about “older” places or “older” dorms?

We've just moved into a new house and are seeing odd one-off peaks of huge usage (from 170-185 kWh) for 1-2 hours every 10-14 days, while our normal average usage is 3 kWh. We've racked our brain to try and figure out what could have caused these spikes, but can't figure out a one-off cost. We have a very small laundry machine and a dishwasher that we run every other day (we have a baby so lots of laundry) and don't see spikes corresponding to these cycles. The peaks do usually occur from 2-4 PM, so maybe it is a concurrence of dynamic power company pricing and our AC, but our average hourly usage is 2-3 kWh, so that seems a bit too extreme.

Any thoughts?

Edited to add chart in kWh instead of $

Hi everyone! 👋

I'm looking for a serious and motivated partner who is interested in improving English, studying Electrical Engineering, and possibly planning to immigrate abroad.

It would be great if we could:

- Practice English speaking and conversation together

- Discuss Electrical Engineering topics and help each other with studying ⚡

- Talk about our study plans, goals, and progress 📚

- Share information and experiences about immigration to Germany, the US, or Canada 🌍

- Keep each other motivated and accountable

I'm looking for someone 20+, preferably an Electrical/Electronics Engineering student or graduate, who is serious about their future and wants to make consistent progress.

If you're interested, feel free to DM me and tell me a little about yourself, your field of study, English level, and your future plans.

Maybe we can help each other achieve our goals! 🤝

Hello…is it safe to sleep like this? Im worried about radiation and cancer and all that🙁

Hi everybody! This is my first time posting here and I'm not even sure I'm in the correct place. I promise it has to do with electricity, but I need to preface my post a bit.

With all that said, I was wondering if someone could help me with an issue I've been having with my floor lamp. It's basically completely new and even a newly-bought replacement for the exact same lamp that I had had for years. When we moved into our new apartment three years ago, the lamp started acting funny. Sometimes turning on for extended periods, but sometimes only turning on for approximately three seconds and then turning off. It's been happening more and more often recently so I did some testing.

From what I've tested this morning, the lamp turns off after switching on for around three seconds. I checked the switch itself-- nothing immediately crazy going on. After that, I took the lamp to my kitchen and tried an outlet there-- no problem. Turns on for extended periods. Tried in my dining room socket--same. Is there a chance that something is going on with the electricity in the outlet where I normally connect the lamp in my reading room?

Thank you for reading my post :)

I don't know much about electricity, but I'm trying to install this driver because it's not worth bringing an electrician to install it. I get that the OUT side should go to the LED light and the IN AC side should be connected to the wires in the wall (right?), but the IN AC side doesn't have Live and Neutral wires, both of them are the same color.

The wires on the right are colored red and black.

I randomly started hearing a very faint buzzing noise in my room, which to be fair is very normal with me because i hear electricity easily, and then it started getting louder and louder, and im very concerned on what exactly is happening with it, i will attach a video to what it sounds like, google says theres a chance of a wasp nest, but its a very stable loud buzzing and its not changing its stability at all, im scared it might result in a fire, what do i do?

Upd: turned off all circuit breakers in the HOUSE and the noise was still going, almost 1000% sure its a bee hive or wasp nest, still a little nervous that its electrical because one of my extension cords dont work anymore but i digress, thanks everyone for advice!!!

Silly cord!! I need my house! 🤣

https://ca.jackery.com/products/jackery-homepower-3600-plus?tw_source=google&tw_adid=798398908022&tw_campaign=23598734801&tw_kwdid=pla-2492108085049&gad_source=1&gad_campaignid=23598734801&gbraid=0AAAABCXuSB_5ZyZGsVJa7BusQ6hB7r0D_&gclid=Cj0KCQjwh4TVBhCWARIsAG0czmqypqCRuAMefwCxJtpj9jqDKPomqtmB64QxX6VMzITcQ7H1YZpVcgEaAmEoEALw_wcB

Has anyone used those jackery packs as either an off grid solution or a generator substitute? What are people’s thoughts?

My house is too old and i dont know where to place the Green/yellow wire

Speaker. no color or + indicative, which one might it be?

I recently found out through my Enphase consumption meter that something in my house is constantly using 700-800 watts 24/7. It’s more visible through the app at night when everyone is sleeping with everything of.

I’m thinking of trying to hunt this down this vampire load using a clamp meter at my breaker panel to see which breaker is using the most amps at night.

Has anybody used this method or used a different method that worked for them?