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.

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1answer
32 views

Fusing on dual voltage industrial device

Please forgive me if this question has been asked before. I am designing a heating device that will be sold to industrial consumers. In our past designs we have had multiple versions of the same ...
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1answer
95 views

Crosstalk between AC and DC

First time asking a question but I've come across something I just can't find the answer to. Whether or not it's because a silly question I hope to find out. So I understand that with crosstalk ...
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3answers
5k views

How to connect this 3 wire AC motor?

I have this NEW heat recovery unit from Amazon (shady quality, branded as made in UK but actually made in China) with this motor inside. It was supposed to have two speeds (Low/Hi). Question: How ...
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1answer
323 views

Balanced delta source to Wye source by considering magnitude only is ok?

I read and derived formulas for balanced delta source to Wye source; it is given by Vy = Vd / sqrt(3)<30 but in some places I see people only dividing by sqrt(3) for conversions are keeping angle 0,...
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1answer
73 views

run ac device on battery [closed]

I recently purchased a radio which unfortunately doesn't have battery option. Its spec is AC 230V - 50/60 Hz and 14 W Is there any way to use my Ni-Mh rechargeable cell battery with this device. ...
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2answers
146 views

Transformer - I connected 50k resistance which burnt - why? AC

Wall supply gives as much power as a component uses. I'm trying to connect a 800W transformer to produce an arc of electricity. But I can't exceed 10A because home fuse will triger (so every device ...
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3answers
198 views

Building AC to DC circuit that can not be run on a breadboard

First I have an AC power source. Can I solder the power source directly to a rectifier to make it DC? I plan on using a protoboard using the DC power but I need the board to be able to handle 2Amps ...
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0answers
50 views

hump on rectified signal and inconsistency on gate signal

Following is the image of my circuit, I am working at the moment. This is not my own circuit but I am trying to understand and work on it. Following is the signal I am getting at Gate2. What could ...
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1answer
204 views

Unity Gain Phase Splitter- Why outputs have different voltages

I’m trying to calculate the values of the biasing resistors for this phase splitter circuit. (I know the actual values of the resistors, but I just wanted to manually work it out). When I made the ...
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1answer
61 views

Why does the TUF formula use \$V_{rms}=\frac{V_m}{\sqrt{2}}\$ and not \$V_{rms}=\frac{V_m}{2}\$ for a half wave rectifier

We know that for a half wave rectifier \$V_{rms}=\frac{V_m}{2}\$ and \$I_{rms}=\frac{I_m}{2}\$ But the Transformer utilization factor uses \$V_{rms}=\frac{V_m}{\sqrt{2}}\$ (But uses \$I_{rms}=\frac{...
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2answers
150 views

230vac / 5vdc power supply design

I am making my own basic bench power supply mainly for testing logic gate circuits, relays, flip flops etc, that I can move around to different locations. The circuit of the entire schematic will be ...
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1answer
91 views

3 phase - Unbalanced loads from line to line

In the case of a 3 phase wye unbalanced configuration such as the following: we can compute the amount of current going through the neutral wire using geometry, in this case it is \$\sqrt{(\cos(150^{\...
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1answer
1k views

Measured continuity between live and neutral

I was trying to get rid of the humming noise coming from my speakers in my hi-fi system. It is an old piece of equipment from back when the UK appliances did not come with the mains plug and you had ...
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1answer
57 views

Can I use 220V inverter as 12V power supply?

I have a pure sine wave inverter, it charges a 12V battery and converts 12V from battery to 220V during a power cut. Since it can output 12V to charge the battery at quite a high current I was ...
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3answers
157 views

AC/DC wattage conversion

I've got some common Dutch "huishoudsnoer" (household-cable? Mainly used for powering lamps. Not solid core, 2*0.75mm² cable) laying around, that's rated for 1380 watts. Our wall sockets provide 230V ...
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2answers
99 views

What is the effect on kWh if the power company reduces line voltage to a residence? [closed]

We just received our power bill and it is showing a 30% rise in kWh for the past month. Nothing has changed in our home. We were even gone one full week in the month. To make it more interesting, ...
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0answers
162 views

Pulse skip modulation vs Phase cutting for AC inductive loads?

What is preferred and safe mode for controlling power to an Inductive AC load when driven by a Triac? I am using a microcontroller with zero crossing optocoupler to drive the control signal and the ...
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3answers
141 views

What enables the home appliances and electronics to work on single-phase?

Talking about the home appliances and electronics, if it is single phase that we are using in houses and currents get to zero every half cycle, how do the home appliances (using AC) and electronics (...
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50 views

DC Variable power supply

I would like some advice on a particular circuit design for a variable DC power supply. Here is some information about what I want to do: I want to do open and short circuit tests on an alternator ...
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2answers
66 views

To run 1.5 ton ac [closed]

i want to run a 1.5 ton ac through dynamo and generater(that run a dynamo) for that purpose how much KVA dynamo required and also a diesel generator(how many hp/KVA) will be required. NOTE:- generator ...
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1answer
388 views

Can someone explain this schematic and how to modify it to add PWM LED dimming?

I bought a LED bulb (AC175-265V, 7W, 59mA) to made some experiments with it and inside there's this circuit: Can someone explain me how this circuit works? The small transformer package with a single ...
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3answers
626 views

Why does a capacitor not discharge in the same cycle it is charging in a clamper circuit?

As far as I understand, in an AC circuit, a capacitor is supposed to charge as the voltage is increasing, and as soon as the voltage starts decreasing, the capacitor starts to discharge (Since it will ...
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1answer
61 views

Replacement for an AC Transformer

I have a model train set that have an AC transformer. The transformer looks like one of those typical adapters where there is a wire connected to the outlet. Then you have a big black box that weights ...
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1answer
87 views

4 channel digital scope

I wish to view 3 phase waveforms from an alternator (DUT) through isolation transformers via a digital oscilloscope. A 4 channel oscilloscope is obviously ideal for this as I can view the waveforms as ...
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1answer
1k views

What is the purpose of a reset button on power strips?

I'm just curious why would someone put a reset button on power strips in which don't usually implement any digital circuitry. I'm sure it's not for discharging any capacitors, since power strips don't ...
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1answer
666 views

AC MOSFET switching without any diodes? [Low-Cost AC Solid-State Relay With MOSFETs]

Is it possible to switch an AC load using two MOSFETs in anti-series such as the picture below? In this mode, each MOSFET is on during one half of the wave and the other's body diode conducts to ...
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2answers
91 views

Small device to detect AC outage

I want to create a small device that detects AC outages and sounds a buzzer powered by a battery. I have some experience working with arduino and DC electronics but I have no experience in working ...
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3answers
104 views

Electric field strength from AC conducting wire in form of a loop along z-axis?

Let's say I want to calculate the electric field strength from an AC conducting wire, with a certain frequency and current. The wire is in the form av a loop. I want to calculate the E-field along the ...
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1answer
518 views

Identify Vintage Power Cord for 1980s Organ [closed]

I Recently acquired a Technics SX-C600 organ but it needs a power cord. Does anyone know what type of power cord I should get for this? My understanding is that this is a rare organ.
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0answers
20 views

Dividing the rotor circuit by slip in induction motor

In this article equation (3), just after figure 5, they divided everything in the equation for current by slip. I understand that current remains the same when doing this, but voltage and power would ...
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1answer
119 views

High(er) Current AC Flasher Circuit

I'm trying to develop a flasher circuit for an aircraft warning light like the one shown at https://flightlight.com/products/obstruction-lights-controls-faa-l-810/. The light will be powered with ...
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1answer
51 views

Synchronous Generator EMI

In the attached image below, I don't understand the text and phasor diagram that I have highlighted in yellow. Why does the induced emf on the armature winding lag the magnetic flux of the ...
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2answers
147 views

Why do we have “live” and “neutral” wires? [duplicate]

Our house wiring is AC. I thought that AC means we have current flowing from Wire 1 to Wire 2, after 1s/Frequency it flips and current flows from wire 2 to wire 1 and this goes on and on. I heard ...
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2answers
92 views

Is miniaturization of office device A/C adapters feasible?

Today I looked upon my desk: as you can see in the screenshot below, there are three plastic boxes containing A/C adapters for (I think all in the 12-20V and 1-2A range): screen device notebook ...
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2answers
167 views

How to maintain a stable voltage on a Wind Turbine for Inverter

I'm doing some experiments on a wind turbine in my spare time. At the moment, my system runs well and I can measure good output values from my generator. For example: 38V @18Hz at 30 RPM 97V @37Hz ...
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1answer
259 views

Synchronous generator induced EMF

I have started studying synchronous generators in more detail of recent and I'm finding it difficult locating helpful information regarding their operation. What is the formula that can be used to ...
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1answer
84 views

How do we get the complex frequency of an exponentially damped sinusoidal function?

In my textbook, Engineering Circuit Analysis 8.Ed by William H. Hayt (Chapter 14, Section 14.1 page 536) I stumbled across a section explaining the complex frequency. The goal is to cover the concept ...
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1answer
46 views

During the positive cycle of US AC MAINS Electricity is the secondary Voltage back EMF or in phase with the AC MAINS?

The Sine wave of AC Mains in the US starts at zero and increases to Vmax~169-Volts. in the beginning magnetic Flux Change is greatest as it is proportional to the slope of the AC Sine wave (which is ...
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1answer
112 views

AC circuit with no neutral output [closed]

(Please forgive my ignorance, this came up when trying and failing to construct a homemade current clamp with no background in electrical engineering.) Suppose I have an ideal wire connected to the ...
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1answer
127 views

What should be switching voltage rating of relay in a 380VAC 3 phase system?

I am hooking up a system where there is 2 sources of power available. One source is the grid power, and the other is a generator. The grid provides me with 3-phase 380VAC with a neutral wire; and on ...
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4answers
101 views

Is this AC circuit wired correctly? [closed]

Is the following AC cicruit wired correctly? And is it safe to plug in if i use electrical tape to cover the open connections?
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2answers
395 views

BJT AC Analysis using r_e model

This is a picture of a Common Emitter Voltage Divider bias and it is been modelled using a CCCS and a diode resistance using the r_e model. Now my doubt is that I get problem in finding the input ...
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3answers
160 views

Do 240V AC switches only need to open the active wire?

I want to add a simple inline switch to a small, mains powered lamp (~240V AC, 10W Max). It's earthed; it has a typical 3-core cable with a 3-pin plug. I bought a bunch of switches, expecting ...
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1answer
354 views

How to calculate current from a phasor?

I'm just working through some textbook exercises and have been stuck on this one for a while. The question is: The current in an AC circuit is represented by the phasor \$I = I_0 e^{j(120\pi t + \pi/...
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1answer
89 views

Ideal Transformer Theory Question

I have some questions regarding ideal transformers, similar to the one seen below: When talking about 'ideal transformers', can I calculate the current on the primary side by finding the complex ...
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3answers
138 views

AC through inductance only

How will we have a current through a pure inductive coil connected with ac power supply? I am confused because the induced emf will be equal to the applied voltage but opposite in direction, \$emf = -...
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1answer
39 views

Behaviour of capacitor while charging

When a capacitor is applied with an AC Wave in a circuit containing only capacitor, it charges to its peak value between the time period of 0 to 90 degrees. My doubt is that what happens between the ...
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1answer
60 views

Measuring direction of current to determine moisture is present

I am building a moisture sensor with an AC current to prevent electrolysis. The AC will be generated with a simple schmitt trigger oscillator with the midpoint reference set at 2.5V. Water would ...
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4answers
494 views

High frequency response of capacitors

I have studied the fact that the capacitor does not like a varying voltage across its terminals, and it acts as a short circuit initially so that there is no voltage drop across it. If this is true, ...
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1answer
49 views

Why does AC/Sweep in Cadence always require a starting and stopping frequency?

It seems as if there is no way to simply test a circuit with an AC voltage source at a single frequency. How does someone test a circuit that plugs into the main voltage at 60Hz? Is it really ...

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