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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2answers
60 views
Phase Angles in Series/Parallel networks
INTRODUCTION:
I've been having a hard time in class trying to understand phase angles. I understand a few concepts which I've stated below for clarity in regards to this discussion.
1.) ...
1
vote
1answer
67 views
AC DC Analysis of diode
in the following circuit:
Im looking to find what \$v_D(t)\$ is given \$V_γ = 0.7 V\$ and \$r_f = 0\$.
Now when doing the DC analysis, find that \$VDQ = 0.7 V.\$
But im having trouble finding ...
1
vote
2answers
55 views
How to use integration or differentiation to optimize frequency in achieving a specific phase angle?
Question:
With source voltage kept constant at 8V peak to peak vary the frequency until the phase angle "theta" Vr referenced to Vs is approximately 45degrees. Record the Vpp value across R1 and the ...
1
vote
2answers
98 views
What does small AC signal mean?
I'm taking an introductory electronics class, the first chapter is about amplifiers, controlled sources, gain, stuff like this. They mention "small AC signal" a few times but never explain what small ...
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0answers
36 views
AC Circuit Analysis (Determining the vectors) Help!
INTRODUCTION:
I'm having a rough time completing this problem. I've arrived at what I believe are the answers but I have no way of being sure if their right. I tried to plug this circuit into my ...
0
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0answers
61 views
Combining 2 sources of ac to provide more power?
I have a device that takes 24VAC.
I have two adapters that takes 120VAC and converts to 24VAC.
One adapter works with the device, but I get instabilities from time to time and I wonder if it ...
-3
votes
0answers
49 views
Testing the problems with earthing at home [closed]
How can I test the current leakage problem of Home due to faulty earthing? Switching all the electric devices and checking out the meter to see whether its running - will that do?
1
vote
1answer
45 views
Building a small D cell battery charger?
I am looking to buy/build my own D cell Nimh battery charger with the following requirements:
-dual prong AC wall input
-charges Nimh D Cell
-is safe
-contained within 1" x 1.7" x 2.2" enclosure
As ...
15
votes
1answer
429 views
Does this device which claims to reduce reactive energy from a house work?
I've opened a device that states that it can reduce the reactive energy from a house, by plugin it directly to the power outlet/wall socket. I think it is a con, so I've opened it and I saw this black ...
0
votes
3answers
81 views
Understanding “Leading/Lagging” and “Phase Shifting” with Sinusoidal Functions?!
INTRODUCTION/QUESTIONS:
I'm reading through a chapter on sinusoidal alternating waveforms and I'm having some difficulty in the section on Phase Relations. The generic expression is mentioned below ...
-2
votes
0answers
26 views
Is there any risk charging a camera battery with a bigger intensity AC adapter than expected? [duplicate]
I use a Samsung ST30 camera, which AC adapter outputs 4.4V - 400mA current delivered by USB port. As a matter of facts, it nicely loads on a computer USB port outputing a probable 5V - 500mA.
The ...
-1
votes
1answer
73 views
Will a 40W incandescent AC bulb operate on a 330V DC voltage?
Will a 40W incandescent AC bulb operate on a 330V DC voltage or not?
0
votes
0answers
41 views
Loading effect problem
i m trying to connect a de sauty's bridge(AC bridge) output to a precision rectifier. The problem is the output of the bridge (AC bridge) changes drastically to 5volts as soon as the connection is ...
1
vote
1answer
140 views
Reading the frequency of an AC signal using an arduino
Basically I have a motor with a magnet spinning on the end. I have a sensor that produces an AC signal when the spinning magnet is placed next to it. It produces a voltage of ±300mV. I want to measure ...
4
votes
3answers
168 views
Driving Permanent Magnet DC Motor via PWM
SUMMARY:
I am currently trying to finish up a DIY project I've been working on for a while: Building an electric potters wheel. I acquired a treadmill and salvaged quite a few good parts from it, and ...
3
votes
2answers
121 views
What is the output voltage of this 555 timer high voltage circuit?
I'm trying to calculate the theoritical output voltage of the following 555 timer high voltage circuit.
It claims to output up to ...
3
votes
2answers
127 views
Converting universal AC to 3.3v DC @ 0.1A
There's a bunch of topics around this but i haven't found something that fits my requirements. I'd imagine this is a fairly common thing though so any pointers would be appreciated
Basically i want ...
1
vote
2answers
81 views
Mosfet Circuits Voltage
So let's take a simple cmos circuit like this:
So I get that for DC analysis \$V_G = 12 \frac{R_2}{R_1+R_2} \$ and then \$ V_{GS} \$ makes sense to me...because there is a constant \$ V_G \$ value ...
2
votes
4answers
277 views
Why can I put an electrolytic capacitor on AC?
I have seen here and there schematics with electrolytic capacitors put on AC. And this sounds weird to me.
Electrolytic capacitors have a polarity, right? If we invert the polarities on DC, bad ...
2
votes
1answer
62 views
Finding values of LRC circuit when frequency is given
I am trying to solve the following question. The original question is:
The given impedances of the series LRC circuit are established at an
angular frequency of 2000 rad/s.
Calculate the ...
1
vote
1answer
61 views
Is AC Dimmer on Vector Board trouble?
I'm building an AC Dimmer based on this circuit (linked) and am considering using a Vector board instead of making a PCB. Does anyone foresee any issues with this? Particularly regarding 120v ...
0
votes
0answers
26 views
Regarding voltage regulation of a synchronous generator
My textbook somewhat ambiguously defines the voltage regulation of a synchronous generator as the difference between the induced EMF and the full load terminal voltage, divided by the full load ...
3
votes
1answer
268 views
Why does a 240 volt outlet save money in electrical cost than a 120 volt outlet?
I live in the US and we have many outlets that run at 120 Volts. I heard that for devices that support the 240 volt standard may not cost as much in electricity prices.
Can someone explain how by ...
2
votes
3answers
93 views
Can supplying DC power into an AC device break the device?
I have an AC device that takes 12 volts 47-63Hz AC. It is a water softner that is essentially an electromagnet. I lost the original plug and supplied it with 11.2V DC, it came on for a few minutes and ...
-2
votes
1answer
126 views
At very high frequency (700 kHz), an AC circuit has a voltage reading 10 times the EMF, why is this?
I've set up an experiment in which I vary the frequency of an electric signal using a waveform generator. The experiment is testing a transformer, but I've encountered a problem on the primary circuit ...
3
votes
2answers
110 views
Why are the power transmission/distribution systems AC and not DC?
Is there a good reason why we are not in the process of completely converting our electrical transmission system to DC? The main reason for using AC on the grid (no offense Tesla, I love you man) was ...
0
votes
0answers
60 views
Safe approach for 120v power box w. 2x Dimmable outlets?
I'm looking to create a 4 outlet AC box (2 of which dimmable by arduino) and am intending the merge these two tutorials.
Although i'm not a certified electrician I do have experience with home ...
1
vote
5answers
162 views
Oscillator circuits operation?
Damped AC oscillations are produced in LC circuit by charging and discharging of capacitor and inductor but how it is achieved through an RC circuit as RC circuit is used in Colpitts Oscillator?
4
votes
1answer
73 views
2 full bridge with 2 secondary winding in series… is it possible?
simulate this circuit – Schematic created using CircuitLab
Is this possible? Think of the center tap transformer as a 2 winding connected in series
1
vote
3answers
107 views
How is current lowered as Voltage is increased in AC power transmission
I was reading about power transmission on wikipedia and came across the explanation of the efficiency of AC power transmission that said power in the load = (I^2)* R while power transmitted= IV. The ...
2
votes
1answer
148 views
Mixing AC and DC power in a circuit
This is likely a noob question, apologies if the answer is obvious.
I'm trying to control a furnace using a 3.3V microcontroller. The furnace operates by connecting a common 21V AC "hot" line to one ...
1
vote
2answers
87 views
DC Voltage Grounded with AC Input
This is an image from a book showing us how to solve BJT circuits via AC analysis:
So I understand that when doing AC analysis to ground all the DC voltage sources but I don't understand why. Can ...
0
votes
3answers
145 views
Is it safe to parallel wall-wart inputs via a single cable?
I have 4 identical devices each with their own low amperage wall wart, and I want to tidy up my power cabling. (They are more like laptop power supplies than wall warts, as they have an AC cable, ...
2
votes
3answers
176 views
AC Adaptor converted in USB charger, is it safe?
Is it safe, or maybe I should I say "logical", to take an AC adaptor and splice the wires, reconnect them and solder together with a USB cable to power a device?
I had an old gameboy advance sp ...
-7
votes
2answers
97 views
Send a signal through the powerline [closed]
I would like to what is the easiest and cheapest way of sending a signal through a 110 volt outlet wiring to another outlet on the same phase or on a different phase. I would like to know if a light, ...
2
votes
1answer
66 views
What is the commonality between a radio, a welding power source and an induction heater?
I was reading into the basics of welding power supply (because I have taken up TIG welding) and inductive heating (because it is part of a number of applications in metal fabrication), and I noticed ...
0
votes
1answer
273 views
Need help on speed control of single phase ac induction motor
I'm working on a project "single phase ac induction motor speed controller". The spec of the motor that im going to use is
230v,1/8hp ,8000rpm@no load
I want to know whether it is possible to ...
3
votes
2answers
128 views
Is it OK to have data lines and AC in the same multicore cable?
I need to provide the following over sections of 1m multicore cable, totaling around 15m.
240v AC
5v DC
GND
RX
TX
Will the AC cause problems for the Serial data?
2
votes
1answer
123 views
Common DC ground with two bridge rectifiers
I have an old AC transformer with many taps off it at different voltages. Connecting a voltmeter to tap 2 and tap 3 gives 25V and connecting it to 3 and 4 gives 5V. I connected them to two bridge ...
8
votes
5answers
580 views
Why do AC-to-DC adapters have long cables on both ends?
Why do AC adapters have long cable on both ends? I believe that almost everyone using one would want it either directly next to the gadget it is powering (even possibly joined together with it if ...
-2
votes
1answer
116 views
what is the purpose of this three coils and switching leaver
I found a strange device on my junkyard,
And it seems like it have made to work with three phase.
But there is an strange thing that I could not understand.
That looks like this.
and that ...
5
votes
1answer
159 views
What is the Thévenin equivalent of the mains power supply?
Thévenin's theorem says that any voltage source can be modeled as an ideal source in series with some complex impedance. How does one quantify this model for AC mains supplies? What parameters are ...
1
vote
0answers
92 views
Lighting relay(?) with 220V leakage insensitive coil
Existing staircase lighting time-automat can not use 220V neon mini-bulb or LED lighted make-contact buttons. - These convenient buttons cause it t false-start (as if pressed) due to their ...
1
vote
2answers
67 views
Will a device capable of receiving a 200 Vrms input signal happily accept a 200 VDC signal?
To the best of my knowledge, Vrms is used to express an AC signal as the equivalent DC signal that would produce the same power dissipated in a resistor R; I believe this is best calculated using a ...
0
votes
1answer
88 views
Can someone explain impedance in simplest way? [duplicate]
I know in DC it is Resistance of the load.
In AC is it impedance of a line correct? can someone please help me understand impedance and types of impedance.
Zero Sequence, Positive sequence and 2 ...
1
vote
3answers
176 views
AC Adapter Input vs Output Power?
I have a laptop AC Adapter thats rated for 19.5v/3.34A DC output for a total of 65W. The input is rated at 100-240V/1.5A AC. My question is what is limiting the output to 65W? It seems like the input ...
1
vote
3answers
217 views
Does a resistor in an AC circuit produce the same heat as in a DC circuit?
Does a 1k ohm resistor produce the same heat in a AC circuit which has an rms voltage of 10 volts (60 hz.) as it would in a 10 volt DC circuit?
1
vote
1answer
122 views
Can I use more diodes to reduce the voltage off a diode bridge?
I have a transformer labeled as providing 9Vac, 3.36 A. It appears to provide 9.4 v ac according to my multimeter.
It runs through a diode bridge (WAB 040 diodes -- already fried the last version), ...
2
votes
3answers
170 views
How do I test how many amps a transformer actually puts out
I have a 120v <-> 9v ac transformer rated at 3.34 amps, but my multimeter suggests that (after running it through a diode bridge), I can get 7+ amps out of it @ 9.4 volts ac.
Can I?
I have a ...
19
votes
6answers
687 views
How precise is the frequency of the AC electricity network?
If I make a digital clock which first detects the AC frequency roughly (whether it is 50, 60, 100Hz, etc), then uses it as its clock pulse source, how precise would it be? Would it work world wide ...
