# Tagged Questions

The tag has no wiki summary.

363 views

### The electricity grid: what keeps small power generators from being 'driven' by large ones?

This is a two part question and pertains to power generation: What prevents a larger plant (say nuclear) from turning an itsy-bitsy gas generator into an electric motor and drive current through it? ...
48 views

### How to understand synchronism?

In my job, I frequently compile a rough rundown of the power consumption of simple industrial plants. Here, you always encounter a "synchronism" factor, besides how many motors of which power and ...
84 views

### How can an inverter transfer energy to the power network?

It is possible to use an inverter to transfer energy from home made produced energy to the main power network. It is not clear to me how this can be achieved. What type of load appear to be the power ...
97 views

### Send a signal through the powerline [closed]

I would like to what is the easiest and cheapest way of sending a signal through a 110 volt outlet wiring to another outlet on the same phase or on a different phase. I would like to know if a light, ...
123 views

### Two power sources, common ground and noise

I'm having the following circuit: Where TWL6030 is a DC-DC buck converter and INA219 is a high side current sensing circuit. My problem is with the power sources,...
1k views

### How to calculate Real Power and Power Factor using an Oscilloscope?

I'm trying to calculate the Real Power consumption of my device in Stand-by mode, but to do that I need to figure out its power factor due to: Real Power = Vrms x Irms x PF Now, my device like many ...
121 views

### Single pole AC to DC conversion circuit

I am thinking about making a remote control light switch that fits into the existing light switch panel. And to power up the electronics that would requires a 3.3V DC supply. The problem is, the ...
402 views

### How does an inverter affect the computer?

I have rampant power failure in my country. So to mitigate, we have an inverter that basically converts the charge from a big lead-acid battery to AC. But as far as i know this doesn't produce pure ...
231 views

### SMPS unit working

Can anybody help me with schematic or links for effective design of an SMPS unit which takes 230v AC and outputs 12 v dc with 2A .... i want to understand how it works how a optocoupler work in that ...
370 views

### Line, Neutral and Ground and another Ground

I try to make a 110VAC energy meter connected to my computer out of the CS5490 This IC measures voltage and current over a voltage divider and shunt resistor respectively and then calculates the ...
943 views

### Why have electricity travel across the country at 1,150 kV?

The Powerline Ekibastuzâ€“Kokshetau in Kazakhstan holds the record for having the highest operating transmission voltage in the world, running at over 1 megavolt. Why did they choose to deliver energy ...
195 views

### what's in this peculiar safety plug?

This unusual plug interfaces an electric hair dryer to the 120V 60Hz mains. The thing that makes it peculiar is that when it is tipped back and forth, a small 'clunk' can be felt, as something inside ...
111 views

### Will there be a problem if I stay almost in the border in trace spacing when dealing with line voltages?

The IPC-2221 standard shows that 1.25mm will be enough at less than 3050m at 250V (220V is the line voltage here in Turkey), even if the coating gets damaged. However, people generally recommend 5mm ...
5k views

### Creepage distance for PCBs handling line voltage AC?

What is the required creepage (e.g. trace-to-trace) distance for PCBs handling 240VAC rms? What about 120VAC? This is for UL and CE certification. The standards for PCB Creepage (e.g. the distance ...
395 views

### mixing multiple power sources

I have 500 watt wind turbine which gives watt around 100-500 depending upon weather condition. I use it for led lighting. total led wattage is around 500 watt. so most of the time not all of the ...
124 views

### What is the IEC standard number for this plug?

I need the specific IEC standard number for a power plug/socket used in a laptop. See the photo below. I need to know the laptop-side plug (the lower plug in the photo). Thanks. This plug is used in ...
152 views

### How is an AC signal offset?

In three-phase the 2nd and 3rd phase are offset by about 120 degrees($\frac{2\pi}{3}$ radians). But how is this achieved? The concept that just each phase is offset by 120 degrees sounds easy but ...
297 views

### First mains-powered project - best practices?

I'm about to commence building a project that's basically a USB-controlled dimmer. I think the main components will be: Velleman K8064 voltage-controlled dimmer Phidget 1018 usb interface board ...
493 views

### What have countries gained by increasing/decreasing mains voltage by 10V?

Reading the list of standard plug and socket types on Wikipedia, I see that countries have made their mains voltage higher or lower. For example, in Mainland Britain (Wales, Scotland, England) the ...
172 views

### Transformer Output Problem

I have this transformer which is 240VAC to 11.4VAC. But when I hook up my multimeter I am only reading about 1.2V. I have my multimeter configured to read AC and the scale is also correct. However my ...
5k views

### Why is three-phase offset by 120 degrees?

For three phase electricity the wave is offset by 120 degrees(2$\pi/3$ Rad). Why aren't the phases closer together? Is it because it will affect the frequency of the phases? How was this 120 degrees ...
573 views

### How to switch many (15) low power (40W) lightbulbs from a microcontroller?

The power rating on the bulb is the amount of power the PSU has to deliver in order for the bulb to light up the brightest right? Hence if it's a 40w bulb I need 40watts of power for it to light up ...
6k views

### Have 60A 220V circuit, want to use one 110V leg of it. Can i?

I have an 220V air compressor (30A) in the attic of my garage. It has a 110V automatic drain valve connected to it. A the breaker box downstairs I want to be able to turn the power off to BOTH. ...
523 views

### Power grids : AC vs DC

We know that we have now 50/60Hz in our walls due to mainly historical reasons - back 100 years ago there were no ways to up/down scale DC voltage. These days we just have problems due to that - ...
422 views

### 21V power supply — 26V output with different mains?

I have an AC/DC power supply (from the UK). It is labelled 230V/50hz. As far as I know, electric in Mainland britain is 240V/50hz. Indeed, the unit did correctly power the Korg keyboard in the UK. ...
2k views

### What is the easiest way to monitor a 120v line via software?

I'm wanting to count how often a water pump turns on, how long it's on for and when it turns off for an extended period of time. My plan was just to monitor the pressure switch, which is at 120v on 1 ...
283 views

### My country's voltage is 220 and I want to recharge a Japanese cellphone (100V), what should I use?

I live in the Netherlands and can't recharge my Japanese cellphone because I think it's due to the difference in voltage. What should I use in order to recharge it anyways? Thanks!!