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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70 views

Does 1Vac matters to a Arduino pin?

I am planning to do a current measurement with Arduino. The board I'm using is mega 2650, operating voltage is 5V (I/O pin limit is 3.3V). And the CT I'm using is exactly the same as this tutorial, ...
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1answer
85 views

AC Mains Voltage Indicator Design

I am a beginner in EE and I am just studying circuits at the moment, and I have this question about designing an AC Mains Voltage indicator that indicates the voltage level of AC mains by three ...
2
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3answers
100 views

Quick and dirty LED power from AC

I have some extra 1n4007 diodes, and was wondering whether, instead of using a power supply to drop the voltage, could I could power LEDs by just making a full wave rectifier, Using a capacitor to ...
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0answers
46 views

Minimum AC voltage that causes nerve damage?

What is the minimum AC(50-60Hz) voltage that can do harm/nerve damage? I know that a few hundred volts (even 100?) has been documented to cause nerve damage that resembles a crush injury. I also know ...
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1answer
29 views

Measuring the output of a phase control triac

I have an air compressor I'm trying to troubleshoot and I'm trying to determine if the problem is with a small circuit board with a triac. The board takes as input an ac wall outlet (US) and outputs ...
4
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3answers
66 views

What is proper polyphase AC terminology?

I'm not entirely clear on the proper terminology for polyphase AC systems. I hear it used informally, but I'm not sure what the proper formal names are, if there are any. How I've got it in my head is ...
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1answer
80 views

Wild AC to DC for Arduino and high power leds

I've seen some similar posts but none did exactly match. I'm looking to power a Arduino Uno and 1x 10W + 4x 3W LEDs (Using BUZ11 from Arduino output) from a very wild AC source which is on a very ...
0
votes
1answer
40 views

Should AC voltage supplied to an external device through a relay be electrically isolated from the main power source of the enclosure?

Given a power supply in an electrical enclosure powered by 120 VAC. An I/O device will trigger a relay with a 24 VDC control. The signal from the I/O device will enable the relay for a set duration. ...
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0answers
33 views

Non invasive voltage detecion (AC 230V 50Hz) Galvanic isolated

I am putting together a PLC (Siemens Logo o Simatic) that will monitor a control line that supplies signal voltage (230V 50Hz) to a industrial sized heating unit (GAS). The control line has in series ...
6
votes
1answer
1k views

Replacing incandescent bulbs with LEDs, unexpected behavior

I have an over-the-stove microwave/ hood vent combo with 2 adjustable-brightness lights. The lights appear to be 12V lamps with a G4-style connector, and they burn out all the time... like every 4 or ...
0
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1answer
59 views

Power opamp 'floating' output

So I had to design an amplifier with a 'floating' output. (I don't know if floating is the right word, it's the direct translation from dutch.) See the picture below ( I drew it whilst sitting in the ...
11
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3answers
1k views

Why don't AC transformers burn up

I'm marginally familiar with the way that an AC transformer works. After viewing this question: Why don't all motors burn up instantly? It got me thinking about the same thing with AC ...
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1answer
46 views

Does low frequency PWM create reactive power in a transformer?

I got a 350VA transformer (230V~/24V~) which is directly connected to a heating unit at it's 24 V ends. The 230V end of the transformer are connected to 230 V~ mains over a solid state relay (SSR). ...
0
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2answers
36 views

Impedance problem (polar to rectangular)

Having a little problem understanding why this example converted polar to rectangular form to get Z. What is wrong with just leaving it in polar form and doing the algebra to get the value for Z
2
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3answers
84 views

AC adapter: Input power vs Output power

When I look at, let's say an iPad AC adapter, the input/output rating on the charger states: Input: 100-240V 0.45A (AC) Output: 5.1V 2.1A (DC) I know that the ...
2
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1answer
82 views

Coupling 14 AWG without Marettes

What options are available beyond marettes to join wires together? I am looking for something that holds 3-5 wires and will be within a portable box (ie will hold together if moved around a bit). Is ...
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1answer
111 views

AC and DC voltage are constant even though the frequency changes

In the circuit below, why does the AC voltage remain constant even though the frequency increases?
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1answer
54 views

Middle-Tapped Transformer Full-Wave Rectifier Vs. Full-Wave Bridge Rectifier

In terms of output voltage, which one of these would be best? Coming into this, I would have to say the center-tapped transformer full-wave rectifier would allow the most accurate output voltage ...
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2answers
86 views

Is there any option to store AC voltage?

Almost every power plants produce Alternating current. It is not necessary that entire energy that they produced are consumed in real time. Does they have any option to store excess energy?
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2answers
64 views

A coil connectd to AC voltage source

Suppose I connect an AC voltage source (frequency = 7hz) to a coil, the coil will resonate and radiate an electromagnetic wave. What's the frequency of the radiated wave and does it depend on the ...
1
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3answers
82 views

AC detection for switching to battery source

I am designing a DC-powered ceiling fan. Fan is working on AC and I convert it into DC when light is out; we attach a 12V battery so that fan runs continuously. I want to make a circuit which senses ...
0
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2answers
72 views

Potentiometer Ripple under load

I have the following circuit with a 10k 0.5w trim potentiometer. simulate this circuit – Schematic created using CircuitLab The voltage after the bridge rectifier is maintained at ~8.6 ...
0
votes
1answer
46 views

AC Transformer Power Cable

I have recently purchases an 120 Vac to 12 Vac transformer similar in design to the one shown here. I am curious as to the best way to wire this up. I am not a big fan of making a suicide cable for ...
1
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2answers
74 views

What transistor or combination of transistors should I use to make a fully controllable AC switch?

Suppose I want to switch AC. I want to control (allow, prevent, or interrupt) current flow in either direction. SCRs won't do because I want to interrupt current, and I don't recall seeing many IGBTs ...
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2answers
159 views

Grounds in AC circuit

I am trying to solve for Vo in the circuit above. The input voltage is a simple sinusoidal with Vp = 100V. And all R=2.2k . What I am confused about is how to deal with the two grounds. How do ...
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0answers
55 views

Need Help in creating a driver for a 220v AC Servo Motor

I am a new to electronics and have been working on to design a Motor Drive for comonly available Serveo motors like: http://www.alibaba.com/product-gs/1580332915/servo_motor_used_in_CNC_machine.html ...
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1answer
87 views

Regulating 220v AC voltage for halogen lamp with Arduino

I am making a project based on Arduino which is about regulating the brightness of 220v AC halogen lamp. I've read that halogen lamps are the easiest ones to regulate the brightness. However, ...
0
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2answers
55 views

Reactive Power (negative P) [closed]

"During the interval that p is negative, power is being returned to the load. (This can only happen if the load contains reactive elements" Can someone explain to me why this is the only case P can ...
0
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3answers
90 views

Low Voltage DC controlling 120 AC, with Arduino

I'm looking for a type of device I can hook my arduino (micro-controller) to that will control a set of lights that require 120VAC. Basically I will be making a light organ, where the arduino will be ...
0
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0answers
71 views

AC 3 Pin Transformer vs 2 Pin Transformer

I am in the middle of learning, and planning to build my own high power 110V AC to 5V DC power supply capable of handling around 15 to 20 amps of power (custom power supply for ~10 Raspberry Pis). I ...
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2answers
85 views

AC bias circuit for a tape recorder

I was wondering if I can "upgrade" a DC biased tape recorder to AC bias with a simple circuit. I found some schematics for AC bias circuits, but they were all very different, and I'm not sure which ...
4
votes
2answers
168 views

Using oscilloscope safely with AC mains

I know there is quite few discussions already on this topic, but since english isn't my first language I though it better to get some more information about this. I have used oscilloscopes to ...
1
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4answers
126 views

How does electricity represent sound?

I understand that AC electricity can travel through wires to represent sound. But, to be honest, I can't find a good explanation of it. Here are my questions: How exactly is this setup? Does voltage ...
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0answers
15 views

about conversion of h-bridge [duplicate]

I want to know whether h-bridge could convert pwm to ac signal If we give 5v pwm signal to input of h-bridge how much voltage of ac signal will it produce.If possible explain clearly please
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1answer
60 views

AC to DC Filter Confirmation

Of the circuit I need to know the name of and what it is; my guess is, is it an AC to DC current converter? Is anyone able to confirm or deny? What does it act as when its all formed together? ...
11
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2answers
831 views

Why AC points on PCB are separated by a hole

I want to find out why, in professional PCB's, they separate between the AC (220 VAC) points on the PCB with a hole in the PCB: Is it for more isolation between the AC lines? Is leaving a distance ...
0
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2answers
215 views

How to convert 6V AC to 5V DC

I'm looking to convert 6v AC (.5A) to 5v DC for use in charging a phone via USB. idealy a relatively inexpensive pre existing solution would be perfect, but I've been unable to find anything like that ...
1
vote
1answer
97 views

Can the discharge when plugging a laptop to a power outlet can do any harm?

In this question the OP ask if (s)he should connect a power source into a power outlet first or into the laptop first. While the question has been closed, i think there is a very valid point to ...
2
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1answer
106 views

Thermography difference between AC current wire and DC current wire?

Is there thermographic difference between AC current flowing wire and DC current flowing wire? And thermogramic differences for drift velocities?
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4answers
109 views

Calculating Impedance for capacitor in AC circuit with some undefined waveform

I need to set up equations for some simple AC circuit. The problem is that I dont know the formula, definition for the resistance. I know for the 1/2*PI()*f*C, but I think this is only valid for the ...
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1answer
135 views

conduction current vs displacement current across capacitor [duplicate]

Kindly help me understand the difference between conduction current and displacement current. Quick searches explain that displacement current is associated with changing electric field, frankly ...
1
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2answers
70 views

Phasor Representation of Sinusoidal Forcing Functions

Lets take a phasor Vm<\$\theta\$ which is equivalent to Vmcos(\$\omega\$t + \$\theta\$) Let us Assume that a forcing function on a network is Vmcos(\$\omega\$t + \$\theta\$) +j Vmsin(\$\omega\$t ...
0
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1answer
88 views

Use CT current sensor to measure AC current of a single device

So I recently bought 3 current transformers with the goal to measure the current of 3 washing machines. All I want to measure is if the machines are running or not so accuracy isn't really a concern. ...
2
votes
1answer
80 views

What is a SRF? (This is used in AC power distribution system with isolation transformer)

Following image shows a block diagram of a AC power system. What is that SRF equipment comes with the isolation transformer? What SRF means and what it does?
0
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1answer
60 views

Phase Difference

$$i_1 = sin(wt +45^0) $$ $$ i_2 = -sin(wt +60^0)$$ Question : what is the phase difference dows i1 lead i2 My method 1 ) Eliminate minus sign that is i2 = sin(wt + 60 + 180 ) = sin(wt + 240 ) ...
2
votes
1answer
280 views

How to sense 24V AC (Thermostat) with a 5V Microcontroller

I'd like to detect thermostat events (heat, fan, ac etc) with an Arduino. I've done quite a bit of investigation but haven't found a definitive solution. Most projects I see involve controlling the ...
3
votes
2answers
93 views

Symmetric power sockets – design considerations in electrical devices

There are various single-phase power socket standards in use. Some countries use plugs that can be plugged in the socket only in a specific orientation (for example, the United Kingdom) while other ...
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4answers
206 views

Use AC-DC adapter instead of AC-AC adapter

I'm building an O2 amp, which according to the designer requires an AC-AC adapter (Triad WAU 12-200) to convert regular wall power to 12VAC. By looking at the schematic for the amp however, it seems ...
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2answers
92 views

Diference Connecting AC/DC

Why is there a difference between how AC is connected and how DC is connected? For DC, the polarity of the connection matters, but for AC it doesn't.
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3answers
79 views

sharing one 110VAC circuit with two high amperage devices

I have a fairly simple need and there may be a commercially available device that does this, but I have not found it. I need to buy/make a 110VAC device that will automatically switch between two ...