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.

281 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
2
votes
1answer
47 views

Laplace tranfsorm of capacitor functions and initial conditions

I may be asking something trivial, but unfortunately, I could not find an answer so far. Suppose an AC circuit. The voltage of the capacitor is given by $$v_C(t)=Q(t)/C = 1/C [ \int_0^t i_C(τ)dτ + v_C(...
2
votes
3answers
91 views

Measuring the waveform of mains voltage using an oscilloscope

I understand this is a recurring discussion, but I still can't find a concrete answer to this question. I would like to know how can I inspect the waveform of my UPS output (230V) using an ...
2
votes
2answers
85 views

Figuring out ground in AC circuit

I'm currently trying to change my lamp in my bathroom so I disconnected my current lamp and forgot to write down what the cables were attached to. There are 3 cables coming out from the ceiling. <...
2
votes
2answers
243 views

How does a RC Lowpass filter work?

So I've been trying to understand how an RC lowpass filter works, and I think I got it, but I just need some clarification. My understanding: So an RC Lowpass filter in a nutshell is just a voltage ...
2
votes
0answers
56 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 ...
2
votes
0answers
93 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 ...
2
votes
1answer
79 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 ...
2
votes
1answer
156 views

Power amplifier simulation and real time experiment mismatch problem

Thanks in advance to anyone who will take the time to read my first post here. At present, I am doing a simulation of a power amplifier in LTSPice. The schematic and relevant files are uploaded in a ...
2
votes
1answer
127 views

My triac turns on when gate attached to vcc (good)… but also when connected to ground (bad)

I'm still really new at working with triacs and understanding them, but I want to make a circuit that allows a microcontroller to turn on/off an AC signal (very low power, not mains, don't worry) to ...
2
votes
1answer
159 views

Is the Gummel-Poon model useful for explaining AC transistor amplification?

Let me be clear: By amplification I am talking about the process of boosting the strength of an AC signal. Thus, where the output power to input power ratio is greater than 1. Now suppose we have a ...
2
votes
0answers
298 views

What's wrong with my input circuit? LTspice

I am designing my first power electronics board in LTspice to convert single phase AC to DC. This DC is fed to asymmetric bridge to drive an SR motor which is connected to a flywheel. This flywheel ...
2
votes
0answers
234 views

Tricky AC power Question

Greetings all, Just to be clear, I am not asking anyone to do my homework. I am simply asking for guidance and or to clarify any conceptual errors I am making. For the following question, ...
2
votes
2answers
144 views

Circuits of AC - impedance

I have a question regarding impedances. While it is intuitive that \$ R \$-element has impedance \$ R \$, it's not so easy for me to figure out impedances of \$ L \$ and \$ C \$. Here is my, probably ...
2
votes
1answer
438 views

ac voltage regulator

I'm trying to built a circuit that amplifies music from a phone to a headset, based om ambient noise level. So if you're surrounded by noise, your music volume will turn up and in silent surroundings ...
2
votes
0answers
896 views

Calculating signal attenuation for AC?

So we've got this; simulate this circuit – Schematic created using CircuitLab Which I've been told is equivalent to the sum of it's Coutputs to an AC signal; simulate this circuit So then; $...
2
votes
0answers
781 views

Why does a multimeter in resistance mode show initial continuity over a diode?

I originally phrased this question very differently; the original text is retained below in case background information is useful to clarify the context. When I using this digital multimeter to ...
2
votes
0answers
305 views

Control DC circuit with an AC lock switch

I am currently adding circuit with a horn and some lights powered by a motorcycle battery. The circuit should be using about 12v 18A. What I want to do is control the circuit with a lock switch. I've ...
2
votes
1answer
122 views

Is there a pattern to where various industrial AC voltages are used?

AC voltages in the "low voltage" class vary quite a bit. I've seen nominal voltages of 208, 220-240, 277, 380-415, 460-480, 575-600, and 690 VAC. Past that I don't see anything until medium voltage ...
1
vote
2answers
44 views

Controlling AC motor with relay vs. switch on motor

Is there a difference in terms of operation between switching a relay connected to mains for an AC motor versus opening/closing a switch on the motor? Would the internal protection circuitry ...
1
vote
1answer
41 views

Power output only when mains power cut and only bu ups

I have a ups in my home.I want to install a fan in my room which run only when the mains power supply is cut and ups is supplying the power.How can I do this.
1
vote
0answers
38 views

Is there a potential earth leakage or is it something else?

I'm facing an issue in my house since last Christmas. When the lights or appliance with motor in any room are turned off/on the TV would go out and come back on in a short span (as if the power went ...
1
vote
0answers
23 views

EMF radiation from an open AC circuit

When I pass my EMF radiation meter near an electricity cable (a cable that is connected to the home mains), it shows me that there is a radiation. But if there is an extension cable for example, and ...
1
vote
0answers
55 views

How can I modify a home standing fan to run at low RPM?

I have a house standing fan 220V AC. I need to do modification to make it run on 15 RPM (revolutions per minute), usually fan runs higher RPM than that. Is there a way to make my fan run around 15 ...
1
vote
0answers
25 views

Using a triac plus an H-bridge to switch DC or AC

I've been working on a controller for inductive loads, and I want the system to be compatible with either DC or AC loads. I've got a 24V to 34V DC boost regulator powering an H-bridge, which is ...
1
vote
2answers
59 views

Why do I get these voltage offsets when modeling an RC circuit with an AC voltage source?

During one of my homeworks recently, I became interested in modeling an editable graph of an RC circuit charge and current with respect to time. I used the formula that was derived step by step in my ...
1
vote
0answers
62 views

Protect DC circuit from AC

First and foremost, I would like to point out that I am a beginner in electronics. I have designed a board that is meant to be connected to 240V AC. However, there is a relay on it that has a 12V DC ...
1
vote
0answers
27 views

Creepage between Phase/Neutral and Earth (PCB Design)

The smallest distance between line and neutral on my PCB is 4mm, which ought to be enough for 240V mains. I had a copper pour connected to earth around every trace with a clearance of 1mm. Someone ...
1
vote
1answer
47 views

what is the importance of input and output impedance of a RL low pass filter?

I read from the book that for a good voltage coupling, the input impedance must be larger than the output impedance of the previous stage, which requires a min value of Zin since the frequency of the ...
1
vote
0answers
66 views

What is the best transistor model for bjt transistor ac analysis(middle response)?

Nowadays I am working on bjt transistor ac analysis. I use r(e) model for bjt transistors ac analysis in my university. I know there are separate methods for low frequency medium frequency high ...
1
vote
2answers
43 views

AC phase current sensing using Isolated delta-sigma modulator

I am trying to design a isolated AC current sensor. I've chosen the AMC1106 Isolated Delta-Sigma Modulator. (change my mind if you think there is a better solution for 220V AC; 2A Max; 0.25%) The ...
1
vote
1answer
71 views

Low Voltage, High Frequency, High Amperage Power Supply Design

For an ongoing project of studying magnetic properties of various metals we need to use a power supply which can generate 25 V peak to peak, frequency 50- 500 kHz, 5A (PP) current. Frequency would be ...
1
vote
0answers
40 views

Phase angle in a series RC circuit

I have a simple question from an electronics textbook (Electronics Fundamentals, Pearson, 8th Ed., p510 Q 37): 10V 10 Hz AC supply, 4.7K resistor and 10uF capacitor in series, with Vout measured over ...
1
vote
0answers
46 views

How exactly does a matrix converter work? Is this even a question that could be answered without months of study?

I learned a while ago about the matrix converter, a type of power electronic device that, I'm told, does direct AC-to-AC conversion without an intermediate DC step. I'm told it can convert input AC ...
1
vote
0answers
36 views

Can I use a plug rated for a DC circuit in a low voltage AC circuit?

I have an spare 2-conductor plug rated for 12VDC at 5A from an old project. I’m now working on a Class II low voltage (24VAC) projet for which I need just such a plug. Is the plug rated for the DC ...
1
vote
1answer
126 views

How to wire an old single phase AC brushed motor to be reversable

I have searched several forums and found a lot of interesting stuff, but nothing yet that really applies to my situation. I have an old Westinghouse FH motor 1 1/2HP single phase brushed AC motor. ...
1
vote
0answers
58 views

Is this the correct AC analysis of the following circuit?

If I have the following circuit simulate this circuit – Schematic created using CircuitLab Is this AC analysis correct? I am not sure if I should add the R4 resistor in series with the re ...
1
vote
0answers
108 views

Importance of the apparent power

It is said that, though only active power can actually do work, we have to consider apparent power to dimension the source. But what would seem important to me for that would be to know the maximum ...
1
vote
2answers
57 views

Induction from AC or RMF

I'm struggling to get my head around induction motors. Specifically, from what I can see the rotating magnetic field created by the 3 phases creates flux lines which sweep across the rotor bars which ...
1
vote
1answer
482 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 ...
1
vote
0answers
86 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 ...
1
vote
0answers
59 views

How is AC load distributed across on-site generation and the utility?

I’m trying to understand the physics behind AC load distribution when distributed on-site generation is installed and the load is also connected to the grid. In the diagram below, I have a building ...
1
vote
0answers
88 views

Apparent lack of rigor in Phasor domain analysis of steady state AC circuits

so I have encountered a hitch in my understanding of analyzing steady state AC circuits. I have looked everywhere for the answer to my question and I can find nothing. Usually when we analyze ss AC ...
1
vote
2answers
83 views

Current flowing in an open circuit to make it the same voltage

I've tried to research this answer for quite some time but i'm struggling to find a proper answer. I think my question falls between antenna theory and batteries. So in a dipole antenna we supply a ...
1
vote
1answer
50 views

I want to handle the voltage and current spikes from inductive load of 220V AC ceiling fan

I am trying to regulate speed of 220V ceiling fan from Arduino but unable to handle the reverse voltage and current though I am applying the flyback diode across inductive load.
1
vote
0answers
55 views

How do portable batteries with AC outlets handle the ground pin/wire?

There are many portable batteries ("power stations") that have AC outlet(s) with – what looks like – a dummy ground pin. From what I can find in their manuals, it doesn't seem like these devices are ...
1
vote
1answer
368 views

How to connect an AC line filter

I am trying to connect an AC line filter (rated for 115/250VAC) on the load side of a 24VAC transformer (part# BPD2G, datasheet here). The first filter model I used is Delta's 03DBAW5. From the ...
1
vote
0answers
129 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 ...
1
vote
0answers
78 views

Measure low AC Power consumption (oscilloscope? MCU?)

I would like to measure AC power consumption of devices such as AC/DC charger, AC LED bulb or an electric circuit in the main box of a house. However, their power consumption are quite low and the ...
1
vote
0answers
957 views

Snubber for Relay Contact Switching Resistive Load

I am working on a redesign of some circuit boards and am looking for a way to save space and potentially switch to surface mount parts. Some of the largest through hole parts in use are for an RC ...
1
vote
0answers
52 views

Transformers and high voltage elements

I've been trying to learn how to properly set up a circuit for power regulation. Often I hear for domestic use that it is better to use a transformer to isolate the device as well as stepping down the ...

1
2 3 4 5 6