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
50 views

Average of AC signal measured with oscilloscope

I'm wondering why the oscilloscope displays that average rectifier ripple voltage value measured in AC mode is higher than zero. Moreover, the minimum value happens also to be higher than zero. ...
0
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1answer
66 views

Wy are speakers rated by impedance instead of inductance?

Audio speakers contain coils which product sound by vibrating a cone. Why are speakers rated by impedance instead of inductance?
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1answer
25 views

Voltage Spikes in AC voltage Controller

The diagram above shows my circuit. It is actually an AC Voltage Controller with PWM controlling the output voltage and a 1:2 transformer stepping it up to 230V. A 1.8uF capacitor is used as a ...
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0answers
23 views

24VAC Power Pack Peak to Peak or RMS Voltage? (For Split Rail Power Supply)

I'm designing a regulated, current limited split rail power supply for \$\pm12VDC\$ and was thinking of achieving this with a 24VAC input plug pack/wall wart. I implemented the power supply with ...
0
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1answer
21 views

DC consumption translation to AC consumption

I've a battery charger that can output 9v and 2.5A and I use full power from it that is 22.5W. Can I translate this power consumption from DC to AC current? My AC is 220V 50Hz, so I'll consume ...
0
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1answer
60 views

How to use arduino nano to switch an 230V AC motor on/off?

I want to switch on and off an 230V AC motor with a relay what is controlled by an arduino nano. The on time and off time would be able to set by a 3-position slider switch. So would be 3 different ...
1
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1answer
107 views

Relay Feedback Problem

I am a computer science student working on a project for my Diploma and I am building a DIY PDU, I thought building something would be a lot funner then programming a website like 90% of the class ...
1
vote
1answer
47 views

Plug from laptop AC adapter was broke [closed]

When I tried to plug my AC adapter was broke. Here you can see it: It's only the wire so I can replace it without any problem from my AC adapter. But my question is: Can I use any wire (while it ...
0
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2answers
33 views

3 phase AC circuit supply potential difference

How can the line voltage be 220 V when in actual line voltage is the potential difference between 2 different lines. For ex:- Vry= 220 V. And why do we divide it by root of 3 to get phase voltage. ...
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2answers
46 views

Doorbell to buzzer with relay and AC to AC transformer

I have the following buzzer and want to use it with a switch by the door. Would the following configuration let this work or are there crucial parts missing? simulate this circuit – ...
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3answers
84 views

Power draw from 120V AC Outlet

According the the following link, a minimum of 4800W is drawn from an electric stove when all burners are turned on: http://www.ehow.com/how-does_5179441_many-watts-electric-stove-use_.html. I'm just ...
7
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4answers
2k views

Why are motor capacitors huge in physical size even though their values are in uF range?

When I see some teardowns of single phase induction motors on the internet, I see their capacitors look like: Why are they that big in size compared to other caps, even though their value is in ...
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2answers
95 views

Why does my Kill-a-Watt read Power of only half the Voltage times Current?

My Kill-a-Watt is displaying that its output is 120 V, 0.16 A, and 10 W. I'm confused... I thought P = V × I from basic EE. Why do I see only half the expected value here? (This is a USB charger, ...
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1answer
62 views

13.8v from transformer

I have an old CB that looks like the Kraco 2555FM and that takes 13.8v. I'm not sure for certain but that is what I can gather from searching the internet. I guess my CB does take 13.8v as well. I ...
2
votes
1answer
28 views

Obtaining Anderson's Bridge Balance Equation

I'm trying to learn Anderson's Bridge Balance equation.I dont know how this value is obtained Why are they equating the voltage drops across branch one and the sum of the voltage drop across ...
0
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2answers
67 views

In a single-phase transformer output, which-wire would be phase, and which-one would be neutral?

In a single-phase transformer input, one wire getting entry as live, another as neutral. But what would be in case of its output? In output, which-wire would be phase, and which-one would be ...
0
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1answer
45 views

Different amperage with a normal and a hook Multimeter?

I am measuring the electric power (P = VI) in a gear-motor. I measure it of two ways. One way is measure with a multimeter the resistance of the motor, then with V=RI, I measure the current, then I ...
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2answers
56 views

Why is DC used in circuit devices? [duplicate]

Why do circuits mostly run on a DC current? I understand that electric motors use AC but things like my laptop operate on DC. Are there another advantages to AC current that made it the standard ...
0
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1answer
18 views

AC voltage regulator in parallel

I have two voltage regulator which works on ac. They are both the same model and provide a maximum power of 3000w. I would like to plug their outputs together to make a 6000w total voltage regulator. ...
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0answers
34 views

AC equivalent circuit -BJT

For the following circuit, I'm asked to give the AC equivalent circuit for small alternative signals. On the second circuit (the one they gave us as a solution), I don't understand why they didn't ...
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0answers
90 views

Circuit for voltage division and DC shift doesn't work

I've connected the circuit below on a breadboard and tested it in the lab: Components: ...
0
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1answer
47 views

Common Emitter amplifier Bias Circuit Simplification

This is a slide from one of my semiconductor devices lectures. I understand how the bias circuit works and how to calculate the resistor values however I do not understand how this simplification ...
0
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2answers
42 views

finding the sinusoidal values of a complex current or voltage

I am having some trouble understanding this type of transformation. The materials provided by my professor doesn't even mention the method that is being used to switch from complex to sinusoidal and ...
3
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2answers
55 views

Do devices on AC currents have flicker on and off?

For current to alternate between positive and negative it must be zero for a split second. Does that mean devices receiving AC current are flickering on and off? This seems like it would have some bad ...
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1answer
77 views

Need advices on an AC fan control circuit

I've setup a small system where I can control an AC Fan by a data-acquisition board's DAC. Here is my final schematics(please left-click to enlarge it): The first issue was to hack the manual speed ...
0
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1answer
30 views

Questions about a relay controlled AC fan setup

I need to switch an AC fan by a DAQ board's analog output. Here is the setup in my mind for the moment: The DAC of the data-acquisiton board can output 0 to 10V DC and can deliver max 5mA current. ...
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0answers
23 views

Feedback on an AC power measurement design

Here is an AC mains power measurement schematic that I tweaked from one of TI's smartplug designs. This simulates well in LTSpice and I was hoping you could give feedback on this. What improvements ...
3
votes
1answer
41 views

AC power measurement query

I'm trying to understand and tweak this smartplug reference design from TI. I'm stumped on the Metrology Analog Filters section on page 1. What I do not understand is why is there a 0R resistor on the ...
0
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1answer
41 views

Power supply - Boost voltage over distances

I'm looking for a good power supply design to boost the DC voltage and convert it to AC so it can be transported over a long distances with low loss. I have drawed a example picture: The only thing ...
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votes
3answers
43 views

AC motor control

I have a simple AC motor, a pump. There is no kind of regulator in terms of speed or pressure. Its supply is 230 Vac, 50 Hz. If I decide to lower its supply voltage, what happens? it will require ...
2
votes
2answers
98 views

Why this circuit has a DC current?

Consider the circuit below: simulate this circuit – Schematic created using CircuitLab If I try to solve this circuit in the frequency domain, I get: $$X_C = \frac{1}{\omega C} = ...
0
votes
2answers
340 views

What kind of generator do i need to run a 1.5 or 2 ton Air Conditioner? [closed]

I am planning to purchase a single AC that would operate on my Diesel generator. My Generator is a 5kVA , 8 HP air cooled one. I want to know that If I have to run only one AC on the generator shall I ...
0
votes
1answer
28 views

AC circuit to act as a relay for another DC circuit

In this circuit, I have caused an AC current to power the gate pin of the Thyristor, which in turn should allow the 10v DC current to pass even after the AC current inverses - it is not a ...
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2answers
45 views

What would happen if we supply dc as well as ac voltage in a circuit? [closed]

How the characteristics of the circuit will change if we supply some dc voltage in an ac circuit ?
3
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3answers
512 views

Why a neon lamp indicator on power strip switch flickers in the dark?

Neon lamp indicators embedded in power strip switches indicate whether the switch is ON or OFF. When the neon lamp is ON in a dark environment (lights of the room are off) the lamp start to ...
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votes
1answer
35 views

AC Line detection using MID400

I want to detect an AC Line Voltage (230V RMS, 50 Hz) and interface it with a microcontroller. I am aware about two solutions. Using an optocoupler like PC817 [datasheet] using MID400 ...
0
votes
1answer
141 views

Controlling a single phase AC fan with a 0-10V DC input

I have a fan motor which is a permanent split phase single phase capacitor motor: http://uk.rs-online.com/web/p/axial-fans/2781543/ I currently control this fan's speed with the following ...
0
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2answers
47 views

Purely Capacitive AC - voltage and current relationship

Studying electronics, capacitors in AC circuits currently. Can not understand two formula's. I see it stated as fact: "In purely capacitive AC circuit Current leads Voltage by 90 degrees." I ...
0
votes
1answer
29 views

AC Analog Isolation

Please excuse my limited knowledge of electronics, my problem is I've a circuit which is driven by a variable AC signal using LabVIEW it ranges from 100Hz to 100kHz (I can lower this to 30-50kHz if ...
1
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4answers
329 views

How safe is a current transformer

I acknowledge that the subject line indicates a "how long is a piece of string" style question, but I hope to make it more specific below. I have a "current transformer" (CT) purchased as part of an ...
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2answers
32 views

How to Series Wire Secondaries of a Multi Winding Transformer?

If I have a transformer that has 3 low voltage secondary coils (3V, 6V, 12V) and 1 primary coil (120V), how can I wire 2 secondaries in series? Can you show a diagram with a load? Is there such thing ...
0
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1answer
44 views

Switching circuit or relay [closed]

I'm new here and don't know much more about electronics.I need a switch/relay that help me off DC line when AC (grid) line is available and automatically turn on when AC (grid) line is not available. ...
1
vote
4answers
374 views

Can a Transformer Have Multiple Secondary Coils?

Can a transformer have multiple, isolated, secondary coils from a single primary coil? Can each coil have a different voltage from the other? If so, is there any large negative effect, and what is the ...
0
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2answers
98 views

AC/DC optocoupler wiring

Looking for some clarification on the proper wiring of an AC/DC optocoupler (HCPL3700, datasheet) when working with 120vac. From what i read online it looks like a need a resistor on the hot side ...
0
votes
1answer
133 views

LED light dimming, TRIAC vs PWM?

Many days ago, I published a question here asking about dimming an AC LED using and Arduino and TRIAC, and I was told that most LEDs that support dimming should work with the circuit I linked to them. ...
0
votes
1answer
36 views

Current Transformer properties

I have a mains track (230VAC, 50Hz) on a custom PCB routed to multiple Solid-State Relays, and I want to measure the power going through this line. I'm looking into Current Transformers (CTs) to ...
0
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4answers
84 views

Why doesn't positive/negative terminal matter in some electrical applicances?

I was wondering why, in some electrical appliances, it doesn't matter which terminal is positive and which is negative, the applicance works anyway. They have plugs like this: An example, the ...
2
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2answers
101 views

Synchronizing a diesel generator with a pure sine wave inverter

As the title reads, I'm trying to understand the best (Practical) way to synchronize a diesel generator with a pure sine wave inverter, in order to implement an automatic synchronizer based on ...
0
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3answers
68 views

Assume AC Phase has zero potential

The neutral null wire is said to have potential 0 while the phase wire has a varying potential. It seems that the potential 0 for ground or null wire is just a definition. One can define its potential ...
0
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2answers
75 views

2 NO reed switch - turn on 230V water heater

For a small home project I would like to turn on a water heater using 2 NO reed switches. Once I put a small magnet ontop of the reed switch (turn the reed switch to Close), the water heater will be ...