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Questions tagged [ac]

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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4answers
29 views

Phase control universal motor dimmer

I need to control the speed of a 220v universal motor using arduino and I am thinking to use an atteny85 ic with a phase control circuit (ltv814 to detect zero crosses and moc3052 to drive a triac to ...
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1answer
22 views

What is the difference between 3 and 4 Pin IEC320 C14 Power Sockets?

What is the difference between 3 and 4 Pin IEC320 C14 Power Sockets? Looking at the picture attached from reseller I cannot see what the 4th pin serves and I cannot find a description anywhere short ...
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0answers
23 views

Running STP and high-current AC cables together

I am about to install a backup generator about 40m away from my house. There is no question what cables to run for the AC current (which will be 230V 50Hz up to 30A) — doubled 10AWG (6mm2) to keep ...
2
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1answer
64 views

EL Wire safety?

Electroluminscent wire is often used on party-shirts or to decorate other wearables. They come with little "EL Inverters" that run on 3-12V DC power. I measured the output voltage that's output into ...
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1answer
33 views

Cap in Series with a DAC Reverse Current

I'm using a 8-bit DAC: (DAC5311IDCKR) to generate a 1.5V Amplitude sine wave with a 3.5VDC offset. I've put high-pass RC filter across it shown below to block DC so that it becomes AC. I understand ...
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0answers
37 views

Maximum power transfer theorem [duplicate]

Im very stuck on where to go with this question. The examples in class used complex numbers, where as this doesn't seem to need them. Im aware that Zs = Zl, but does Zl=Cl+Rl? Any help with how to ...
2
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1answer
52 views

Are large pulsed currents the most deadly type of electric shock?

As opposed to sustained electric shock via DC or AC? I might be wrong, but when people are killed by electrocution it is usually due to a large current of very short duration passing through their ...
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3answers
153 views

Physics of Dirty Electricity? [closed]

I've been reading about "dirty electricity" lately and while I know there's much controversy whether it causes adverse health effects this question is not about that subject. I'm simply trying to ...
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1answer
60 views

Is this mains switch on the Neutral or on the Live wire? [closed]

I'm changing the chandelier in my living room and I would like to double check whether its switch is on the live or on the neutral wire. I have a test lamp which is rated to measure 125-250V. There ...
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0answers
25 views

How can I test which mains wire belongs to neutral and which to ground? [migrated]

I currently live in Spain, in an old building, where apparently electrical codes don't strictly apply... because not all outlets have ground or, indeed, not all connections are grounded. To make ...
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0answers
47 views

How to get AC power supply for projects?

So im planning to do electrical and electronics projects in my upcoming 2 month summer vacation. I bought some books for this (Example Getting started in electronics by Forrest) But I soon realised ...
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1answer
24 views

Clearance distance and resin filler

I'm designing a circuit to detect presence of AC line voltage. It's actually a very simple device with AC side made up of a 200Kohm 1W resistor and an optocoupler and a protection diode. There will be ...
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1answer
25 views

AC signal analysis: Voltage dip (amplitude dip) at time = 0

I'm working on a series RLC problem where the input voltage is a sinusoidal function for all time. The catch is, for t < 0, the sinusoidal function is of greater magnitude than t >= 0. There is no ...
0
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1answer
58 views

Non-zero primary current under open-circuit test

Ideally the primary current should be zero under the open-circuit test. Could someone explain to me what are the physical effects corresponding to the two equivalent-circuit parameters that cause the ...
0
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1answer
82 views

Why are oscillators 'always' AC coupled with 1000pF?

Most of the time I see oscillator datasheets or datasheets for parts requiring external oscillators, the oscillator output is AC coupled to the part it's driving through a 1000pF MLCC. This ...
1
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1answer
79 views

5VDC and 10VAC on the same PCB - what happens on 10V goes to 5V ground?

Me and a colleague (we are both EE-trainees) had a chat the other day about mixed voltages on the same PCB. She pointed out an interesting question that I was not able to solve. Imaging having a PCB ...
0
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1answer
69 views

Best way to power 120 VAC fog machine with DC?

OLD: I have a 120 VAC 400 W fog machine. I want to mount this on a robot that can supply 12 volts. Can I just reuse a $10 car inverter from Amazon or is there a better way to do this? UPDATE: So I ...
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2answers
99 views

Why do we still use high voltage at home (on sockets) in the 21st century? [duplicate]

Just wondering, most of all equipment at home have components/circuitry inside to transform high voltage (AC) into lower voltage (mostly DC), also all modern LED lambs. Modern products become more and ...
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0answers
20 views

Attenuation factor

In A.C. Circuits if R=2k ohm and c=2 micro farad what is the frequency at which the attenuation factor A drops by 20% of its maximum value? In the attached picture my attempted to solve the question . ...
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0answers
35 views

Interfacing with a Nest Hello 'chime connector' module

I currently own a Nest doorbell that uses a "chime connector" between the doorbell wires and doorbell chime as shown below. I have tried to create a digital doorbell chime that will wirelessly ...
2
votes
2answers
51 views

AC Voltage: Wild Reading: phase-neutral & neutral-ground (240V/120V)

I'm getting some unexpected readings when testing a circuit for my wall mounted AC&heat. I'm on standard USA 120V/240V split-phase/three-wire AC power; the specific circuit is 240V. here's a ...
1
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2answers
30 views

Is the input voltage on power adapters RMS voltage or peak AC voltage?

For example, would a laptop power adaptor with a voltage input of 100-240V ~ be safe to use in a country with 230V RMS wall voltage? Thanks in advance!
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1answer
53 views

How to detect the phase sequence of a 3-phase ac (R-Y-B or R-B-Y) using Atmega32?

I am using an 8-bit AVR microcontroller in my project to detect the phase sequence of a 3-phase AC supply. Which method shall I use to do the work with the least number of components required along ...
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0answers
34 views

How does this stator work?

This stator is out of a Wisconsin VG4D gas motor. Both black leads go to a rectifier. Red and white leads go to a regulator. White lead pigtail goes to ammeter gauge and on to battery. I need to ...
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2answers
46 views

HCPL3700 - 220V sensing circuit

I want to use HCPL3700 optocoupler for sensing 220V (line). I design a circuit but I want to ask some questions. HCPL3700 is an open-collector output so I pull-up Vout. In AC voltage sensing some ...
2
votes
1answer
60 views

Can I use DC to run an AC device in some cases? [closed]

I think there may be devices specified to use alternating current (AC) which can run supplied with direct current (DC) instead. There are devices which depend on AC in some fundamental way, like a ...
1
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0answers
84 views

TRIAC broke (literally) – why?

I have built a circuit according to Dimming 230V AC with Arduino, with two output channels. The basic principle is: An ATtiny does zero detection via an optocoupler; when AC crosses 0 V, it triggers ...
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votes
1answer
49 views

Parallel AC Sources

Hello. I am new to electricity. I currently have 3 DC-AC inverter to drive 3 EL Wires(electroluminescent). The input of the inverter will be 12VDC and the output will be 90VAC. I would like to ask ...
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1answer
40 views

AC transmission just requires live wire, why is neutral present

If I touch a live wire and stand on the ground I will die because a circuit is completed, so for any load if I connect one end to live and other to ground it should work right, then why is neutral ...
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0answers
47 views

What is maximum symmetrical output voltage swing in this case?

I'm pretty new to Electronics and hence the following doubt. I could not understand how the authors reasoned out the swing limits for this problem ((b)-part only)
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3answers
72 views

Choosing capacitance for recifier

So I'm trying to use a couple of rectifiers. Specifically, the "NTE5326" and the "36MB120A." I've tried following videos on how to calculate for a smoothing-capacitor but to no avail. If you use ...
1
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1answer
59 views

Seeking simple circuit for converting 5vdc to ~15vac

I picked up some sample smart materials because I have a small project that I want to put 'magic glass' on the outside of so to speak. I picked up a couple of different sample pieces from a couple ...
1
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2answers
32 views

Compensating voltage drop in circuit

My brain seems to be stuck on this very basic circuit design question. I want to power a 24VAC load (solenoid valve) with the help of a switch (triac). This switch, however, creates a voltage drop of ...
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2answers
65 views

How to remove 50 Hz, 100mV noise? [closed]

I am getting 100 mV noise signal at 50 Hz. I do not know the origin of the noise. What should I need to do to remove it?
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1answer
30 views

lower ac current from speedsensor

I have replaced my car gearbox with one from a newer model. All works fine except for the speed sensor. The old one had a speed sensor with a toothed wheel and the new one comes with just the sensor. ...
2
votes
3answers
186 views

Why is this camping light deadly?

I am learning, so go easy on me, if you can. In a video with BigClive, he takes apart a camping light and says it's deadly when you have mains plugged in and usb plugged in at the same time. In that ...
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1answer
46 views

What is the difference between commutation number and pulse number in?

My question is about bridge rectifiers in power electronics. I guess the jargons are too vague, so i quote the exact definitions from my book which i don't understand at all: m represents the ...
1
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1answer
87 views

device suitable for generating AC voltage?

I want to test my circuit with different types of inputs. Is there any device or equipment that I should buy for generating voltages? I would like to be able to adjust the voltage and current by ...
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2answers
51 views

Dividing in Polar form

When dividing in Polar form 31.2/5.74 becomes 5.44. The angle for 31. 2 is 0. So when it comes to solving imaginary number 12. 8 why is the - 12.8 degrees?
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1answer
55 views

Which way should this capacitor go on this circuit?

Which way should this capacitor go on this AC Hysteresis Synchronous motor circuit? Which terminal is CCW and which is CW?
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2answers
72 views

Measuring power draw of more complex loads such as switching PSU

I'm trying to create an extension cord capable of measuring the power draw of devices connected to it. My approach is using a microcontroller with a non-invasive HWTC current sensor. I am using an ...
4
votes
2answers
79 views

Finding phase shift between the voltage and current

I am trying to find the phase shift \$\phi\$ of this circuit. I am using the formula: $$\phi = arctan{\frac{X_{L}-X_{C}}{R}}$$ Substituting in the values: $$\phi = \arctan{\frac{2000\Omega-4000\...
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0answers
48 views

A general math problem that pertains to resistors in AC circuits

I've been reading from this website as a refresher on basic circuits and circuit components. I have no problem understanding the properties of resistors in circuits and how to calculate V, I, or R, ...
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2answers
47 views

Why EL814 (Photocoupler) not specify the max/min input voltage?

datasheet I have an EL814 IC, when I am going through datasheet I got maximum forward current rating 60mA but not getting max/minimum voltage at the input. Ss it possible to apply any voltage range ...
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votes
1answer
50 views

What is the most efficient way to increase the frequency of a waveform?

More specifically, I have an electric induction kettle. From what I understand, it heats the water by sending a high frequency (voltage?) signal around ~24kHz. This high frequency signal causes a ...
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3answers
122 views

Why is the frequency of the response same as that of the forcing function in a linear circuit?

Why is the frequency of the response same as that of the forcing function in a linear circuit? What's the case when the circuit isn't linear?
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1answer
62 views

Mains power transformer ratings

My question is about load currents from AC transformers. If for example, we take a 3 phase step down transformer (11kV to 415V) with an apparent power rating of 100 kVA, the following equation, S = ...
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1answer
104 views

5 volt power supply directly from 120 volt

I would like to use a microcontroller to drive a TRIAC (Z0103MA0,412). The TRIAC will be switching a 120 volt a/c resistive load. I would like to derive a 3 volt or 5 volt CD power supply directly ...
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3answers
64 views

Connecting transformers in parallel.Will this be a problem?

I am creating a power supply as a small project. I am planning on using two transformers (in parallel) to create a positive rail and a negative rail. Will this cause a problem ? I have researched ...
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3answers
88 views

Eliminate AC noise from DC supply?

I have built an automatic water tank using the circuit given below: But this circuit was working well for 2 days. But after that, it triggers falsely. When a fan in another room is switched on, this ...