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
15 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
203 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
56 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
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1answer
51 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 ...
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0answers
21 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
247 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
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3answers
87 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
99 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
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2answers
88 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
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0answers
54 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
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5answers
126 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
66 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
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3answers
82 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
129 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
81 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
130 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, ...
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1answer
106 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 ...
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2answers
90 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
63 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
164 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
115 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
94 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
563 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 ...
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votes
1answer
113 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
148 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
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0answers
78 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
66 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
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1answer
83 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
144 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
202 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?
