This tag refers to alternating current mains power. It usually applies to voltages with >100V RMS, but can also be used for ex. 24V industrial AC power.

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50 views

AC power cord different on a laptop and a desktop, other appliances

If I look at the power cord plugged from the wall socket to desktop computers, monitors, etc. at the office, it looks like (North America): Now, if I look at the power cord plugged into my laptop's ...
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0answers
46 views

Can I use a capacitive divider to run an AC/DC converter from a higher voltage than its rating?

Suppose I have an AC/DC converter rated to run from 120-240VAC, and I want to run it off 480 VAC. I think I should be able to put two capacitors in series as a voltage divider, and run the converter ...
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2answers
113 views

In general, what does the negative voltage or positive voltage represents? [on hold]

whether the negative or positive voltage represents the direction of the current flow?
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1answer
25 views

AC Dimming of FAN making humming noise

I have achieved FAN Dimming using Phase chopping method, here I get smooth dimming on Incandescent Bulbs and I am also able to dim FAN using the same. But during FAN dimming it makes a lot of humming ...
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2answers
73 views

Why is there a 66 Vac reading on the metal shield of our AC socket?

Today, out of curiosity, I took a measurement between the water pipe (presumably to be ground) and an exposed area of the AC socket with metal shielding (supposedly to be ground as well), and got an ...
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1answer
25 views

Minimum current draw of AC to DC converter at no load

I wanted to know if there is a minimum current draw on the AC to DC converters from the AC source when it is connected to an input voltage of 120V (60Hz), when no load is connected at the output of ...
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3answers
416 views

Voltage dropping capacitor doesn't work?

I connected a voltage dropping capacitor in series with 220v AC supply and I measured the output voltage and it was 220 v too. I was expecting to get a voltage that is less than 220 volts. Did I make ...
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0answers
42 views

2-State Wall AC Switch [migrated]

What happens to load in electrical installation which is switched by 2-State Wall AC Switch, when switch is not fully in ON or OFF state, but in middle state? Can that middle state damage load or ...
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0answers
59 views

Power Consumption [on hold]

I have a power supply circuit. It is a power supply unit with 32 AC output channels. And I do not know how to calculate power consuption. What I know is , I am givin 60 Volt DC, from power source ...
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2answers
33 views

Find which wires are what in a sjt power cable

I'm trying to figure out what wires are live, neutral and ground in my computer power cable. I'm getting some weird readings from the wires. ...
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2answers
86 views

Using a 12v switch in 120v circuit

Can I use a 12vdc switch rated at 16A on a 120vac that only use 0.5A-1A? I have a similar switch, that is 120v rated at 10A, but it's a little too small. doesn't fix.
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5answers
1k views

Could most AC devices run off of DC rather than AC?

To be clear - I have absolutely ZERO intention of ever doing this. But when I learned what a rectifier does (flip the negative portion of the voltage into positive), it occurred to me that it ought ...
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1answer
87 views

AC Watts to DC Watts Calculation

Okay, so I'm new to the whole electricity field and I'm trying to get a handle on something so I apologize for any ignorance displayed here. I've purchased a new graphics card for my computer and I'm ...
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2answers
35 views

Quick question about phase displacement in AC circuits

Z1, Z2(impedance) and the effective value of I2 is given. My question is whether I can assume phase displacement of the current I, let's say 0º. I can finish the analysis of the circuit easily this ...
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3answers
134 views

Short analysis of AC circuit

simulate this circuit – Schematic created using CircuitLab For this AC circuit it is known that $$\omega=10^4 \text{rad}/\text{s},L=0.1\text{H}$$ Find capacity of a capacitor, so that the ...
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0answers
32 views

Charger failure safety measures

Suppose I use a charger to power a circuit and suddenly a component inside fails and the 220 volts can easily reach my project,flowing trough the now broken charger.What can I put between the charger ...
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0answers
36 views

Short-circuit when switching off TRIAC circuit

I'm developing a circuit to control electric lamps using a TRIAC. I tested the circuit and it can switch on and off the lamps without any problem. For tests I'm using a regular light switch to cut the ...
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2answers
39 views

Calculate power supply for step down modules

i'd like to build a system in which there will be step down modules that get their power from an ac-dc converter. there are 5 modules connected to the ac-dc converter (each of them steps down to ...
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3answers
79 views

How to convert 220V AC @50 Hz to 400V @ 20KHz?

Sorry, I may be asking simple question but I'm not specialized in electronics. What I want to do is to increase the voltage from 220V AC to 400V AC. Also I want to increase the frequency from 50Hz ...
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1answer
124 views

Why AC voltage is always divisible by 11? [closed]

I started doing by B-Tech today and in the first class my professor asked me this question: Why AC voltage is always divisible by 11? And google searches gave me multiple answers so I would want to ...
11
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4answers
954 views

Schuko plug wiring

Why it is not important where we connect our hot and neutral wire when connecting them to our Schuko plug? Is it because current flows in both directions? It is only important that our ground wire ...
1
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1answer
42 views

AC resettable fuse

I am designing a circuit that plugs into a 12VAC source and I'd like to add a resettable fuse/PPTC for over-current protection. There's plenty of info on using such fuses for DC but I can't confirm if ...
3
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1answer
49 views

DC--> AC Inverter Connected to a single battery in a 6 battery series

I have 6 x 8V batteries connected in series (i.e.48V) and have a 48V smart charger attached which charges them from regular electricity main supply. What happens if I connect, say, a 24V DC to AC ...
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0answers
26 views

AC relay switch-off optimum phase?

I have a circuit which turns a 230V 50hz AC motor on and off by use of a relay. I've tried to arrange it so that the relay would be turned off when the current through the motor is zero. Of course, ...
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0answers
13 views

Circuit Breaker Upgrade Complications [migrated]

I'm currently renting a unit in a commercial warehouse complex. Each unit has individual MLO panels inside the unit, and then a large split meter base with individual breakers for each unit in a ...
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2answers
32 views

Measuring low voltage AC current with a multimeter

I know that with DC you can measure current by putting your meter in series with the positive supply. I have a project running off a low voltage AC supply. Can I do the same?
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1answer
51 views

How can I cause my oscilloscope to trig on interruption of AC voltage?

I'm probing a point with 230V RMS voltage inside a machine (don't worry, I'm using a 100:1 CAT 3 probe rated at 600V), and would like to trigger my oscilloscope at the point when this signal is ...
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1answer
77 views

Why is Rack Mounted Step-Up Transformer Not Industry Standard?

I'm tasked to source a 1U step up transformer so that customers with only 120 VAC mains power can utilize 240 VAC for our products. I've contacted TrippLite and APC who both offer a 2U (2 rack unit) ...
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1answer
72 views

What happens if there is a fault in the neutral wire between the grounding pole and the centre tap of the transformer?

I was reading through some SE questions/answers on residential power transmission and came up with two scenarios I'm unsure about: Assume that your house is wired properly (with no degradation), but ...
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8answers
4k views

Why does a capacitor block DC and not AC? [duplicate]

If someone can explain why a capacitor blocks DC, but not AC, with some math, I will understand all of that much better. I know that there are picture animations illustrating this, but I really want ...
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2answers
89 views

Capacitor safety

After looking at some posts,I started wondering if using capacitors,especially electrolytic ones is as safe as I thought.After making sure that the you don't supply a bigger voltage than the rated one ...
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2answers
66 views

Connecting multiple devices which work on DC to a single adapter

I have 8 biometric devices which run on 12V 2 amps power supply. I have only one AC power source. Usually these devices are connected through individual power adapters. Now I cannot connect more ...
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1answer
48 views

How to make a latching/unlatching relay circuit with 240V converter

I want to make a circuit that at the touch of a button turns on a 12V circuit controlling LED lights, powered from 240VAC. So I need a latch/unlatched relay circuit after a 12V converter, and I've ...
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1answer
48 views

What is the difference between a magnetized nail and a coil?

When I was a child, I brought a nail (metal bar) and I made some turns around the nail. It was something like a coil and the nail was the core of that coil. When I applied DC on the coil using 1.5 V ...
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1answer
34 views

Computing capacitor voltage through series connected diode

I have been trying to analyze this circuit and calculate the maximum voltage across the capacitor. Here is the diagram: And, here are the graphs for various inputs and the resultant outputs: ...
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3answers
148 views

Why the diode has higher impact on dc characteristics than ac?

Consider this circuit which consists of a DC bias and an AC source connected with a diode and resistor: Source: Boylestad and Nashley book 11th ed. Using superposition theorem the circuit was ...
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3answers
82 views

Why AC socket polarity is important?

In North America sockets and plugs design makes sure you'll be able to plug only in a certain way: (source) Why is this important for AC? Moreover, many plugs, such as cellphone chargers, are in fact ...
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2answers
576 views

Will the lower frequency of 50Hz AC affect overall charging time? [closed]

I'm using a voltage converter to go from 220V to 110V to charge a small appliance. The recommended charging time is 6-8 hours. However, this is specified for US AC voltage 110V@60Hz, whereas the ...
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1answer
73 views

Voltage drop-out after lightning strike

A powerful thunderstorm rolled through my area yesterday and something happened that I had never noticed before. Many times before when powerful thunderstorms with lightning rolled through, the AC ...
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5answers
128 views

Why can't everything be run on AC? [duplicate]

There are a few thing that can run directly off of AC power like incandescent light bulbs and and electric motors but it stops there. Most electronics need power converted to DC before it can be ...
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0answers
25 views

Modifications to Neon Sign Transformer to turn it into a variable DC power supply?

I would like to turn a neon sign transform into a DC power supply. Looking into this it would appear I need some rectifiers to turn the AC output into DC. I could use a variable resistor to adjust ...
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0answers
43 views

Single Transistor DC TO AC Circut

I have a question that may be rather difficult to ask and format however I will try. Now I am very new to electronics in general but in my spare time I play around with them a little bit. I have ...
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1answer
34 views

Controlling LED Bulb Dimmer via Microcontroller

I have several (Cree LED bulbs) that I would like to dim via microcontroller. According to Cree the bulbs are dimmable with compatible dimmers. A local hardware store here in Canada has one of the ...
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2answers
176 views

Why are home appliances and other devices made to operate on dc?

Why are home appliances not designed to work on ac?why cant we just stepdown the incoming 230V and design the systems to operate at low ac voltages,instead of converting ac to dc?
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1answer
37 views

Clamp Meter Working Principle

Basic theory of clamp meter to measure rms of current wave. What I have in mind is that wire creates the changing flux that induces voltage in the meter.This voltage is calibrated ? Also how does the ...
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1answer
79 views

AC Wire Resistance

I stumbled across some unexpected data points when measuring the AC resistance of magnet wire. I varied the frequency of the AC voltage and measured the corresponding impedance of half a meter of 32 ...
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0answers
52 views

Proteus Sine Current Source Simulation Issue

The circuit below is being simulated in proteus isis v7 Current Source has Amplitude value 5A (as asked by Proteus). Two Resistors of values 3 ohm each and then there are two AC voltmeters ...
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3answers
105 views

Optoisolator with EL wire won't turn off, TRIAC works fine. Why?

I'm pretty new to electronics, and I'm making a circuit to control EL wire with a DC logic control signal. Specifically, I would like to blink the EL wire with the output of a 555 timer. My first ...
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0answers
52 views

Is there a good book on designing for electrical safety with AC mains power? [closed]

Is there a good book on how to design for electrical safety, particularly when using AC/mains power? I have look on Amazon without finding anything that seemed appropriate. This topic is largely ...
2
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1answer
386 views

What does it mean if an AC motor has two voltage ratings?

On my AC motor nameplate, it says V230/400 (delta/star). I imagine this means that it is compatible with both voltages, but what allows it to do this? How will the performance change for each?