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.

learn more… | top users | synonyms

0
votes
0answers
6 views

How does AC Passthrough work?

Having seen this implemented in devices such as Power line adapters I am interested in how this works in practice. What would need to be considered in implementing this in a product? Is power ...
0
votes
2answers
28 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?
1
vote
1answer
47 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 ...
0
votes
1answer
71 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) ...
0
votes
1answer
52 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 ...
24
votes
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 ...
1
vote
2answers
85 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 ...
1
vote
2answers
54 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 ...
0
votes
1answer
28 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 ...
-2
votes
0answers
32 views

interfacing current transformer with ADC (ANALOG to digital converter) to show the line current on seven segment [closed]

i am working on a circuit to to display the motor line current through digital ammeter using 8051 microcontroller and seven segment display instead of general analog ammeters.please help me in this ...
0
votes
1answer
47 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 ...
1
vote
1answer
32 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: ...
0
votes
3answers
135 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 ...
0
votes
3answers
76 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 ...
3
votes
2answers
544 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 ...
1
vote
1answer
67 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 ...
0
votes
5answers
126 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 ...
0
votes
0answers
23 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 ...
0
votes
0answers
40 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 ...
0
votes
1answer
30 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 ...
-2
votes
2answers
161 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?
1
vote
1answer
34 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 ...
0
votes
1answer
68 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 ...
0
votes
0answers
44 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 ...
0
votes
3answers
95 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 ...
2
votes
0answers
48 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
votes
1answer
362 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?
0
votes
2answers
1k views

AC powering lamps [closed]

Alternative current flows back and forth,generating sine waves at a certain frequency.Then,how can it power lamps,without making them flash continuously?Is its frequency high enough not to let them do ...
0
votes
2answers
122 views

Need to convert 0-10VAC (alternating current) to 0-3.3VDC (direct current)

I am using a sensor that outputs a 0-10 VAC (alternating current) and I need to convert this signal into a signal within 0-3.3VDC (direct current) to feed into an ADC. What is the best way to go ...
0
votes
2answers
83 views

Can a voltage source be DC and generate a sawtooth signal?

Pretty much what the title says. I'm fairly confused with this simple question. Shouldn't waveforms which change amplitude be AC? EDIT: So this is about a RAMP Type DVM (Digital Voltmeter). Can the ...
3
votes
1answer
83 views

Do AC voltages on datasheets refer to peak voltage or Vrms?

I'm attempting to find a relay to switch UK mains voltage (230Vrms); this gives a peak range of approximately 325V, -325V. Consider something such as the datasheet for this relay. It has a ...
0
votes
2answers
46 views

24 VAC source unable to drive servo motor

Here's my power supply (schematic except without the transformer since my source is already at 24 V AC and using a 100 uF electrolytic as my smoothing capacitor): 24 VAC rectifier -> 100 uF smoothing ...
0
votes
0answers
35 views

Analyzing a circuit with given effective values, freshman EE

Here's the circuit: simulate this circuit – Schematic created using CircuitLab Values: Voltage shown at the volt-meter, 11V Current shown at the ammeter, 5A Current generated at the ...
0
votes
1answer
24 views

quick question about AC SPST rocker switch

I'm replacing the motor control switch in this toaster and wanted to be certain about how it should be installed. It's a normal SPST neon rocker switch with A, B and C for terminals, and B-C being ...
0
votes
2answers
67 views

What do these symbols in ac connectors stand for?

I'm trying to use a relay to control my house lights with a electronic circuit. I'm familiar with 5V DC circuits, but I've never played with AC before. My relay has three connections, which I assume ...
0
votes
2answers
56 views

controlling a DIY spot welder with a momentary push button switch?

I have a 240v to 12v transformer even bigger than a microwave transformer and i want to control how long it is switched on for in the range of 50-300 milliseconds to spot weld things. I was thinking ...
0
votes
3answers
84 views

Why is the capacitor considered lossless, even if it can store/give out energy?

They say capacitor is lossless because average power is 0.But contradicting this is the fact that the energy stored/disipated by a capacitor is (1/2)CV^2.How and why is this?
2
votes
2answers
68 views

What are the differences between an AC and DC coil relay?

If a DC coil was just a coil, it would saturate. If an AC coil was just a coil, the magnetic field would drop to zero at 120 Hz and the relay would chatter. Presumably the designs in some way prevent ...
0
votes
0answers
35 views

How does buffer prevent loading effect?

Buffer is said to be used for impedance matching and preventing high flow of current.But how does it prevent Loading effect?How does usage of buffer overcome the dependance of the terminal voltage ...
2
votes
2answers
65 views

Low Voltage AC Smoothing Capacitor Calculation

I have a 9V AC source which will have a max load of 100mA. I'm trying to figure the value of a smoothing capacitor with less than a 10% ripple. I don't have a scope or else I'd just try a bunch out. ...
0
votes
1answer
53 views

Good way to switch AC/DC (Rectifier) in welder

I am building a homemade welder out of microwave oven transformers. I would like to have ideally an on off switch and then an AC/DC switch or just having one switch would work too. AC 120V 60Hz ...
0
votes
1answer
58 views

This circuit has floating nodes in LT Spice?

This is the circuit I'm working on. This circuit probably doesn't work as intended to begin with, but that's not the point. LT Spice keeps complaining that it doesn't have a reference to ground. I ...
0
votes
1answer
30 views

AC steady state circuit analysis using mesh

I have attempted multiple tries into this circuit problem and I am getting no where. For this question I have to use mesh analysis to find \$V_x\$. \$V_x\$ is across the right branch containing the 3 ...
2
votes
2answers
111 views

Does any company manufacture American AC power plugs with insulated pins?

In Australia and some other places, good-quality AC power plugs have "insulated pins". This means that there is a short length of insulation covering the base of the pins. Darren Yates writes that ...
0
votes
1answer
29 views

Finding current in AC circuit, coupled coils

Freshman introductory problem, AC circuit.Coupled coils. Here it is: simulate this circuit – Schematic created using CircuitLab So I need to find the current through the voltage ...
0
votes
0answers
36 views

Calculate lower-bound for the total average power

I'm studying for an exam and have come across a question question about power lower-bound. In my lectures we have gone through AC peak voltages, \$\sqrt{2}\cdot V_{RMS}\$, I'm not sure if it's related ...
0
votes
0answers
111 views

How to measure AC voltage without a voltage divider using microcontroller

I have to measure AC voltage of the mains supply 180-220 VAC through a microcontroller. I have been wondering how to measure it without using a voltage divider. Since the resistance may wear out with ...
-6
votes
1answer
81 views

How or where can I get a 120VAC to 3.3VAC power supply?

I'm using a safety gas valve (commonly found in household stoves) for a hobby project. The valve is rated for 3.3VAC, 3.6Amps. The problem is that AC-to-AC power supplies are quite rare, and I had no ...
0
votes
2answers
112 views

why do rectified voltage boosts after adding a capacitor?

So I found this 9V 1A AC power supply laying around and decided to make a DC source. I rectified and added a capacitor to make things a bit even. After adding a capacitor my voltage boosted from 9V ...
1
vote
2answers
60 views

What would be the results of two bridge rectifiers in series?

What would be the side-effects of placing two bridge rectifiers in series? The question stems from reading how some devices are manufactured with a bridge at the input to make reverse polarity ...