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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1answer
47 views

How to get started with AVR Microcontrollers? [closed]

I have an AVR ATMega32A Microcontroller, a Programmer that supports my microcontroller, a breadboard and some electronic stuff ...
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1answer
67 views

Microwave rotating plate

I noticed that the rotating plate of many microwave ovens usually rotates with a specific direction, even if sometimes this changes. What makes the plate rotating clockwise/counterclockwise? I know ...
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35 views

How to find current and voltage of a certain appliance connected to an outlet?

Objective: I'm new to electricity and trying to convert my mirror integrated with LED work with a power bank. I need to find how much voltage and current is needed to make it work. How can I measure ...
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47 views

How to solve for V0 in the next circuit

How can I solve for V0 on the next circuit if Z1 = 1, Z2 = j, Z3 = -j. All the ways I'v tried, V0 depends ends depending on V0, maybe using superposition theorem? Attempt 1: ( Calculating current ...
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4answers
3k views

How can there be a current without a voltage?

Recently while trying to understand inductive AC circuits better, I got very confused with a question. Let's suppose we have a purely inductive AC circuit with ideal wires and a switch. Let's also ...
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25 views

Simple voltage presence monitoring with negative power supply

I am switching a 230-240 V load with a TRIAC and relay while also monitoring the presence of voltage on both ends of the load (i.e. not measuring the amplitude -- just that the switch successfully ...
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34 views

Using Thévenin to find I3 current

i'm an engineering student and i've come across this problem i have to use Thévenin method, even though i could find Zth by "short circuiting" the power sources and opening the circuit at I3, i'm ...
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3answers
150 views

Question about ideal transformers and inductors

Recently I was studying about alternating currents and transformers and I got confused about some of the concepts. I tried a lot of sources but none of them seemed to address the problem. I ...
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2answers
37 views

Phase Lead and phase Lag

I find the concept of phase lag and and lead quite confusing. Suppose we have two voltages \$V(\theta) = V_{max} \cdot \sin(\theta + 30^o)\$ and \$V(\theta) = V_{max} \cdot \sin(\theta + 60^o)\$ ...
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1answer
37 views

Series Resistance-Capacitance Circuit

I have an optocoupler and I connect it to 230V, the datasheet tell me the optocoupler has a forward voltage: IF = ± 5 mA VF - 1.5 V, so, for limiting the current I need an resistor of 4.7K - 11wats, ...
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1answer
19 views

HCPL3700M optocoupler: why is pulse generator connected to both AC and DC pins?

I'm reading the datasheet for the HCPL3700M AC/DC to Logic Interface Optocoupler. In a test circuit diagram, it shows a pulse generator connected to both the AC and DC pins (see attached). Why would ...
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29 views

AC model and Gain of a two stage amplifier

[![enter image description here][1]][1]I am trying to understand how to solve this exercise but i am having a hard time doing it. It is asked to make the small signal for low frequency(without ...
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16 views

AC connecting disconnecting?

I had a circuit that I wanted to turn on when I connected a plug(9 pin) 3 pins consumed by POT and 2 For a momentary switch. 4 pins remain available. Thoughts was to use 2 pin connected together to ...
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22 views

How to get max V output from XBox360 power supply

I have a few Xbox 360 power supplys laying around and want to repurpose for led light project I am working on. The rated output is 12V 16.5A and thats perfect for my needs Problem is how do I get ...
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33 views

Using current divider to see how much current goes inside the plane when lightning strike

I am working on a project that requires me to understand how engineers do current analysis. The aircraft has a metallic body which provides a path for lightning when it strikes but what if there is an ...
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2answers
94 views

\$V_o/V_s\$ of given circuit

I'm trying to calculate $$\frac{V_o}{V_s}$$ of the given circuit, but don't really know what to do with the voltage dependent voltage source. As I'm not an engineering student, this stuff is very ...
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9answers
4k views

Cheap and safe way to dim 100+ 60W Incandescent bulbs

For my wedding reception, we are building ~25 lighting fixtures with 4 bulbs each (fixture per table for dinner). For aesthetic and budget reasons, these are 60w "Edison-style" bulbs which we want to ...
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1answer
31 views

Homework: AC circuit analysis correctness equations using nodal analysis

I've been struggling to find the equations needed to find \$V_o\$ and \$I_o\$ for the circuit given below. I came up with the following equations using nodal analysis and wanted to ask whether they ...
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1answer
81 views

acs71020 Connecting and reading voltage properly

I am using an ACS71020 3.3V I2C version hooked up to ESP32. I have connected the IC as proposed in the datasheet. Rsense used is 1.8k ohm as proposed in the evaluation board user manual for 230-240 ...
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0answers
16 views

EV charger testing BS7671 CPC-earth test

As part of the standards for BS 7671 it states: A device which disconnects the charging point from the live conductors of the supply and from protective earth in accordance with Regulation 543.3.3....
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34 views

What material of a core put into the inductor would decrease the current?

Consider the \$AC\$ circuit: For various \$U\$ values set by the potentiometer, we have measured the current \$I\$ flowing through the circuit with and without core put inside the inductor \$L\$. As ...
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1answer
24 views

wiring Tamura 4 pin hall effect current transducer to differential daq

How do i wire a 4 pin hall sensor: 200A model below https://www.mouser.com/datasheet/2/397/L03SXXXD15-469349.pdf I don't understand the wiring schematic below I currently have +15 to pin 1, -15 to ...
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1answer
46 views

Wiring 220 to AC/DC transformer help?

On this AC/DC power module the terminals are labeled N and L, can I wire 220 line to line both to N and L? See link to part https://www.mouser.com/datasheet/2/468/RAC10-K_277-1661832.pdf
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1answer
26 views

Forward Voltage VF Max 1V does this mean that the full wave w10 bridge rectifier can only allow 1 volts via it

I want to use a full-wave bridge rectifier. My circuit needs 2 amps of current and operates at 12volts (12V @ 2A). I found this https://www.tanotis.com/products/vishay-2w01g-e4-51-bridge-rectifier-...
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26 views

Changing an AC Signal with a MAX9926

We are using a MAX9926 in Adaptive mode to detect zero crossing of a crank signal. Its mode cannot be changed (PCBs made) however we have a particular use case where the signal presented is as ...
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1answer
30 views

Lower ac voltage from 18vac to 12vac for Christmas fiber optic rotating motor and light [duplicate]

This picture from another thread online relates to my situation: (original) I have a transformer from 240v ac to 18vac but need to step it further down to 12vac. What size resistor should I use in ...
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1answer
45 views

Arduino AC Motor Control and Automation? [closed]

My question is about the automation of single phase AC motors. I am aware that I can purchase TRIAC controllers with manual knobs or even 0-10V control inputs. I am new to the world of AC ...
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1answer
57 views

Have I calculated the peak rectified V and diode I correctly?

A 240V (rms) 60 Hz mains supply is fed to a trans which has 20:1 ratio. The output v from the 2nd winding of the transformer is connected to a full-wave rectifier circuit and a 10kΩ R. Assuming ideal ...
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0answers
47 views

Multiple home appliances emitting the same high pitched noise

About two weeks ago, I came home and noticed a piercing high-pitched noise in my room. After searching for the source of this noise, I found it was coming from my PC's power supply unit. Later that ...
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1answer
29 views

How to calculate time interval between current and voltage waveforms

Is it basically, phase angle / angular frequency? Also for a ac circuit with a single inductor is the phase angle going to be always 90degres, likewise with a circuit with a single capacitor?
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1answer
60 views

AC Induction Motor Constant Speed Control without Tachometer

I want to run the AC induction Motor at a constant speed with LOAD also without Load. So I am controlling motor speed by TRIAC. I can control the motor speed, but my problem is:- I don't have a ...
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3answers
60 views

Full Bridge Rectifier - Voltage Drop Under Load

I am trying to get 5v DC by rectifying the output of a microwave transformer i rewound (the transformer gets approx 4.2V AC on the secondary winding). I managed to get approx 5V open circuit ...
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0answers
30 views

Eagle Net classes not working

I am trying to modify my Net Classes to be wider to run AC current through. (25mil). However, when I add a new class and then try to autoroute it doesn't use that new class. I get an error saying The ...
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58 views

An electronic component differentiating the current twice with respect to time

Say a AC voltage source, V, provides current to a circuit with a resistor, R, and inductor, L. Then my equations to be solved, in terms of current will be: $$ V - Ri - L\frac{di}{dt} = 0 $$ I would ...
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1answer
32 views

Diagnosing a chattering AC fan relay

The diagram below shows the control circuitry of a heating system. I am trying to understand why the wiring depicted here caused the fan relay (PC90-360Q) to 'chatter' constantly when powered on. ...
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33 views

Controlling a series of LEDs ( AC->DC via bridge rectifier)

I'm working on a PCB (Christmas Present) to take in A/C to a string of LEDs and control them (with transistors? and a microcontroller). This is a bit out of my league, but it is making me learn ...
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1answer
62 views

Designing PCB with AC Live and Neutral on two layers

I'm designing a smart socket that will route 240V AC Live and Neutral to a voltage regulator and also to a relay that will control the current flow. Due to the limited space, it will be easier to ...
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2answers
46 views

Floating Conductor Next to AC Power Source

Let's say I have a conductive metal sphere connected to a 50Hz 1kVrms AC Power Source referenced to Earth ground. About 3cm away, there's an identical metal sphere suspended by a non-conductive ...
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72 views

Measure 220V alternating current with a multimeter in DC mode

What happens if we measure 220V AC from wall socket with a multimeter in DC mode (instead of AC)? If I remember correctly, it should show the average value of this sinusoidal 220V, i.e. 0V. Is ...
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3answers
76 views

Controlling the speed of a single speed AC exhaust fan motor

I have this single speed exhaust fan: 30" Exhaust Fan with Shutter - Direct Drive - 1/4 HP - Single Speed. When it's running it's way faster and louder than I'd like it to be. So I'm trying figure ...
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0answers
35 views

Combining AC and DC components in same Spectra/Molex Microfit connector

I am making a control unit. It will interfaced with AC devices like fan, pump, light along with one DC device, namely, a Solenoid lock. All the devices will be placed outside of the control unit. I ...
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1answer
90 views

Variable Frequency Drive with AC motor, 30kW

I have a VFD that controls an AC motor which compresses air. It is an 30kW motor. I have set the parameters required to drive the motor and it runs the motor but not properly. During the test the ...
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2answers
47 views

Do I need a fork terminal to install #8 into an 38660 Molex Barrier Strip?

Can I strip a half inch of wire from a #8 cable and screw directly into a 38660 Molex connector? Or do I need to buy a spade terminal. This is for an AC connection to the back of a DC power supply, ...
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2answers
63 views

Physical connection of AC and DC voltage sources in series

in many circuits (Amplifiers, Filters etc) at the input terminal I saw a sinusoidal voltage together with a DC term, i.e. a voltage like v(t) = sin(wt) + 1 [V]. We may imagine that this signal is ...
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2answers
67 views

Phase difference between resistor and inductor voltage in an RL AC circuit

In my textbook, it is given that \$\mathcal {E} = -L\frac{\Delta I}{\Delta t}\$. The graph of resistor voltage (\$V_R\$) and inductor voltage (\$V_L\$) in a series RL AC circuit is given similar to ...
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0answers
60 views

Why should the primary winding of the transformer not be grounded?

I've been wondering what would happen if you grounded both star points of a Y/Y connected transformer. This shouldn't affect the voltages, so why really is it not advised to earth both the primary ...
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3answers
101 views

Computing the voltage across a parallel LC component at resonance?

Problem For the circuit illustrated below, I am trying to compute the sinusoidal voltage across resistor \$R_{1}\$ when the parallel LC component is in resonance: I setup my problem with the ...
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1answer
25 views

Current flow in trailing edge dimmer

I was trying to learn something about dimmers for light bulbs. After some reading, I found that most trailing edge dimmers contain some variant of this: Found for example in this diy-project or this ...
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1answer
67 views

Is there any hope for this power supply to work on 220V rather than 110V? [closed]

I stupidly moved my laser printer with me overseas without checking whether it would take 220V. I assumed it would be like my desktop computer and accept both. Anyway, here I am with a 110V printer ...
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1answer
54 views

Best way to generate 26 Volts AC at 380-420Hz?

I have obtained a military vibrating-reed frequency meter that I would like to turn into an educational display unit, with a knob that adjusts the frequency from 380 to 420 Hertz, giving the user the ...