We’re rewarding the question askers & reputations are being recalculated! Read more.

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.

Filter by
Sorted by
Tagged with
1
vote
1answer
98 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
votes
2answers
192 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 ...
-1
votes
2answers
122 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 ...
0
votes
0answers
24 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 . ...
0
votes
0answers
331 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
102 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
vote
2answers
36 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!
0
votes
1answer
98 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 ...
0
votes
0answers
55 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 ...
0
votes
2answers
204 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
166 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
vote
0answers
114 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 ...
0
votes
1answer
78 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 ...
0
votes
1answer
62 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 ...
1
vote
0answers
118 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)
0
votes
3answers
91 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
vote
1answer
78 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
vote
2answers
57 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 ...
-2
votes
2answers
101 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?
0
votes
1answer
44 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
209 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 ...
0
votes
1answer
80 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 ...
0
votes
2answers
68 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?
1
vote
1answer
72 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?
0
votes
2answers
92 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
108 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\...
0
votes
0answers
50 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, ...
0
votes
1answer
65 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 ...
0
votes
3answers
143 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?
1
vote
1answer
85 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 = ...
0
votes
1answer
155 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 ...
1
vote
3answers
338 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 ...
1
vote
3answers
189 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 ...
0
votes
1answer
143 views

AC mains rectifier issue

I built a simple full bridge rectifier with AC Mains input, but I noticed that: When the input is 220 V rms the DC output is only 293 V, but I expected the DC output voltage to be 220 x sqrt(2) = ...
0
votes
0answers
29 views

Harmonic function phase shift question

What does a phase difference between two harmonic functions mean ? Why is it expressed in degrees/radians ? Isn't a 360deg phase shift the same as a 0deg phase shift ?
0
votes
1answer
55 views

Whats a technique that I am not aware of to pull an AC cable through a conduit that is just a little to small

I have a lamp I am trying to rewire with one of those bendy necks I can get the cable inserted 75% of the way through the conduit but then the cable and me don't have enough strength to keep pushing ...
6
votes
4answers
2k views

How does residential electricity work?

I'm trying to understand how the electricity works in my house. I live in the US. I know that at the transformer, the primary winding induces a current in the secondary winding. The secondary ...
0
votes
1answer
94 views

What is the reason that moving iron instrument can measure both AC and DC but moving coil instrument can't?

What is the reason that moving iron instrument could measure both AC and DC but moving coil instrument can't? ( moving coil can't respond quickly as the AC changes its direction so stays at zero - is ...
5
votes
6answers
9k views

What is going wrong in this circuit which supposedly should step down AC to arduino friendly voltage?

So I'm using this circuit but when adapter output is disconnected and only midpoint terminal of the transformer is connected the Arduino input pin reads some mV. mid point reads perfect 2.5V. What am ...
0
votes
0answers
141 views

Wiring AC motors in parallel

I am having some Somfy motorized curtains installed in my home, but I struggle to understand the following statement in the manual: Wiring multiple Sonesse 40 WT's in parallel will result in damage ...
1
vote
1answer
39 views

Example of Electrical Apparatus that draw leading VARS and Electrical Apparatus that draw lagging VARS [closed]

I understand that an AC inductive circuit will draw lagging vars while a capacitive AC circuit will draw leading vars (ELI the ICE man), but what are some examples of real-life electrical apparatus ...
1
vote
1answer
46 views

Alternating Voltage

Is AC the same as an alternating voltage ?
0
votes
1answer
56 views

How do I calculate the voltage across a capacitor when the source is a square wave?

I have a series RC circuit with R= 2.2K Ohm and C=100 nF, and the voltage supply is a 2.5V peak square wave. And I'm not sure how to calculate the voltage across the capacitor.
0
votes
3answers
195 views

How does one determine the type (AC v. DC) and operating voltage of small motors?

I've become fascinated by Rolling Ball Sculpture (RBS) and plan to start building my first one soon. Typically a RBS uses a low-voltage, low-RPM motor to carry the marbles to the top of the structure ...
0
votes
0answers
37 views

AC Current Source - Modifiable Amplitude and Frequency

Just a heads up, I am not an electrical engineer. I need to build an AC current source of the following specifications. I have looked into IC chips, but none meet my specifications. I have started ...
1
vote
2answers
81 views

Clipping an AC line voltage

I've got a linear step-up transformer (120V AC input) which has an output that under load nominally supplies 230V AC @ 100mA. But with no load it floats to as high as 280 V. I need to switch the load ...
-2
votes
4answers
280 views

Why does a capacitor charge faster when there is a diode connected?

In an series RC circuit why does a capacitor charge faster when there is a diode connected in parallel with the resistor? I tested on an oscilloscope, using a square signal and this is what I got. ...
2
votes
1answer
89 views

Why is there 130V between my laptop charger ground, and Raspberry Pi 5V Supply Ground?

I noticed that I was getting mild shocks while touching my plugged in laptop and touching a metal shielded USB device plugged into the USB port of my Raspberry Pi 3 at the same time. I used a multi ...
1
vote
1answer
151 views

PSpice AC Circuit Simulation Showing 0 V for Output Voltage?

I am trying to run a simple Op Amp simulation. My lab gives zero instruction on PSpice, tossed us a brief manual on DC PSpice circuits (even though the class is AC), and said go forth. The circuit I ...
2
votes
1answer
88 views

How to measure 0.02V to 0.18V audio signal with arduino?

I have a Sony STR-DE845 home theater amplifier with 8 Ohm speakers. I want to measure the voltage sent to the speakers to infer their volume using an Arduino. The AC voltage measured across a speaker ...