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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15 views

What are the disadvantages of using NZC Optocoupler as switch

I've bought some MOC3023 to use with a triac for turning some home appliance on/off using an EPS8266. The thing is.. every place that I search says that for on/off the best is a zero crossing detector ...
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5answers
184 views

AC circuit relationship between impedance, current and supplied voltage

I am a high school student and currently studying AC basics. In an AC (sinusoidal supplied voltage and current) circuit, resistor voltage and current are always in phase, the supplied voltage and ...
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2answers
35 views

chip to enable Vac 230 when circuit closed

I am looking a IC that could potentially resolve an issue I have on a project. I am using two reed switches to close the circuit when two magnetic contacts are close enough. This will close the ...
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3answers
43 views

Why is a secondary transformer winding for VT filament heater connected to rectified output?

Ok I know this is a pretty narrow question. I'm learning about vaccum tubes, and I think I have the basics down, but this particular setup is confusing me. See the attached picture. In the given ...
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2answers
41 views

Calculating loss due to emission of EM waves (AC)

In AC due to the fact that electrons are accelerated back and forth they emit electromagnetic radiation. Electromagnetic radiation must depend on the value of AC because more accelerated charges emit ...
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4answers
2k views

Is it ok to connect 60Hz inverter to 50Hz transformer?

I have a car inverter (DC 12V to AC 240V). Inverter's frequency is 60Hz. I want to connect the output(240V) of inverter to an ...
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2answers
2k views

Why -5V is 80V compared to GND after a power supply?

I was quite shocked when I realized that negative is not continuous when compared with neutral, and that a negative wire can actually have a positive voltage. For example, this simulation: I am ...
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1answer
3k views

Use ACS712 current sensor in two-phase electrical system

I'm thinking about using the Allegro ACS712 current sensor for measuring house equipment current consumption (for example TV). The issue I'm facing is that my house energy supply is built around two ...
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10answers
2k views

Why is the fuse connected to the live wire?

As far as I can understand the concept of AC, it does not matter which wire is live or neutral as this changes like 100 times per second (implying 50Hz) I believe. I read the fuse must be connected to ...
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2answers
452 views

Explanation of a sample circuit for the FL5160 Dimmer controller

While looking for dimmer circuits, I stumbled upon the FL5160 Dimmer controller and it's specification at https://www.onsemi.com/pub/Collateral/FL5150-D.pdf The example schematic (for example, the ...
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1answer
149 views

Laplace tranfsorm of capacitor functions and initial conditions

I may be asking something trivial, but unfortunately, I could not find an answer so far. Suppose an AC circuit. The voltage of the capacitor is given by $$v_C(t)=Q(t)/C = 1/C [ \int_0^t i_C(τ)dτ + v_C(...
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2answers
58 views

AC signal combination

I have a question about combining two AC signals into one. For my project I need to convert stereo audio to mono audio. For the conversion I used this circuit: I made this simple circuit on my ...
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Basic AC circuit and KCL

AC Circuit Hi, I am a freshman in electronic engineering. I am taking electronic circuit. I don't quite understand how to come up potential difference across the capacitor. I thought the p.d across it ...
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4answers
3k views

Can we tell which way AC power is going through a cable without cutting the cable?

Assume we have a very long cable whose ends are not visible or accessible. One end we know is a generator, and the other a load. Can we determine which end of the cable has the generator attached ...
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1answer
282 views

Can you smooth mains A.C?

I know you can smooth DC with a capacitor but what if you have an unstable mains AC voltage (here in the UK that's 240V 50Hz)? Are there components that can be used or products one can make/buy for ...
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2answers
44 views

AC overvoltage protection using zener diodes(+some other things)

I am considering building an AC protection circuit using the following schematics. I am a physicist and have little practical experience with implementation of electric circuits. Looking forward to ...
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2answers
373 views

Current draw on the AC input of a PSU

I have a cheap PSU of this sort, used for my 3d printer. It has a 110V input, and a 12V output with 20A maximum current. Unfortunately, it doesn't have detailed specs/data available beyond that. Now, ...
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1answer
74 views

Resistance and energy cost in an AC circuit

I’m learning on my own about EE concepts. According to Ohm's law if voltage is constant then current and resistance will affect each other primarily. I believe most household AC circuits provide ...
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0answers
34 views

Convert DC in/out circuit board to AC? [closed]

My team and I are working on redesigning an electric air pump for our client company, with the main goal of converting it to a battery powered unit, as opposed to relying on external power. We have ...
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1answer
56 views

Does differing mains frequency affect DC motors?

I moved a large, high-quality kitchen appliance (a stand mixer) intended for use in North America to the UK. To operate it without damage to the motor, I will need to (at least) convert the voltage ...
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3answers
26k views

Why most appliances in US don't have third prong

Most other plugs I encountered have three prongs - hot, neutral and ground I assume. For example all BS 1363 plugs have one. Also CEE 7/7 have ground connections and while CEE 7/16 exists it is not ...
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2answers
32 views

Delta to star transform currents

When we transform a delta circuit to a star circuit it is easy to transform the voltages and the resistances. In the case of a delta circuit between current flows only between 2 nodes while in a ...
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2answers
547 views

How can I measure an AC magnetic field using a linear Hall effect sensor with an Arduino?

I have a SS49E Hall effect sensor. I want to measure the magnetic field in gauss using an Arduino analog output. I have code for analog applications but is this appropriate just for the DC magnetic ...
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0answers
80 views

Why can't the 3MHz data signal injected into the secondary side of a wireless power system be picked up on the primary side by a coupled inductor?

I have two LC circuits consisting of a coil (L1 and L2), coupled inductor (L3/Lr3 and L4/Lt4), and a capacitor accordingly (Cp and Cs). Both sides are tuned to approximately 300kHz resonance frequency ...
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1answer
60 views

Effects of low frequency in a genset

I am working in a oversized genset that has 150 kW - 180 kVA capacity but it just has a demand of 20 kW, for this reason the control system try to maintain engine velocity but as the load is so low it ...
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2answers
99 views

Disadvantage of low load on a electric generator

I have a generator set that is oversized, it is capable of produce 180 kVA but I just demand 35 kW, it works with propane gas as fuel for primary engine. My question is, which are the disadvantages of ...
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0answers
32 views

Low power factor in Oversized generation set [duplicate]

I have an oversized generation set that works with propane in gas phase,it has 150 KVA apparent power and 120 KW effective power at 0 netters over the sea level,it primary engine is a GM vortec 5.7 L ...
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2answers
98 views

Electric generator fuel consumption while load is increased

I am working on a gas plant that produces its own energy with an electogren group that operates with LPG as fuel. I noticed that this plant is oversized. It has a capacity of 150 kVA but the plant ...
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1answer
57 views

Total power output a generator is able to produce [closed]

I have an oversized generator, it has 150 kVA and I am only using 25 kW. If the power factor is determined by the load, how can I determine the total surplus of energy that I could generate if I would ...
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0answers
33 views

How can I simulate 5VAC from Analog Discovery 2

I'm using an Analog Discovery 2, with the Waveforms software and I'm trying to simulate a scaled-down mains voltage 5VAC, but I'm not sure I understand the output of my Analog Discovery. The mains ...
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1answer
63 views

480VAC to 230VAC AC AC conversion

I want to drive a single phase motor (230V, 260mA) on a 480VAC (phase to phase) source. I made this simple circuit using a 2uF, 600V AC capacitor, simulated it, tested practically and it is working as ...
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1answer
353 views

Nest Protect gen 2 battery to POE

Hey all i am looking for some advice in how to go about my project with a Nest Protect gen 2. In my home i have ran cat6 wire to all 3 locations that require a smoke detector. These cat6 cables are ...
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1answer
41 views

Using a signal generator and power amp to supply >>240VAC to a coil

On Lenz's law, Wikipedia says: Faraday's law states that the EMF is also given by the rate of change of the magnetic flux where epsilon is the electromotive force (EMF) and \$\phi_B\$ is the magnetic ...
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31 views

How to understand AC to DC circuit for dual-slope ADC ASIC?

So this circuit is from ICL7106 datasheet, dual-slope ADC ASIC, what I want to understand is the circuit connected to IN HI and IN LO. So to understand at what my confusion is I need to tell what I ...
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1answer
112 views

Sign of 3-phase instantaneous reactive power and phase sequence

For three-phase systems, in p-q theory instantaneous reactive power is $$ q = \frac{(v_a-v_b)i_c + (v_b-v_c)i_a + (v_c-v_a)i_b}{\sqrt{3}} $$ (see, e.g., [1] Eq. (5)) If we substitute in expressions ...
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2answers
166 views

Is it possible to amplify an AC low level signal with a simple DC source?

The project has an input from -1V to +1V for input. I need a linear 0 - 5Vpp output with the same wave frequency (60Hz). I tried this (and other configurations), but never get the output I need. I ...
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1answer
109 views

How to measure AC voltage using non-linear opto-couplers?

I am designing a TRIAC LED dimmer circuit. Depending on the AC voltage applied, I control the gate trigger angle for the TRIAC to reduce/limit the current at 15 amperes to the load. Gate trigger ...
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1answer
43 views

Separate "voltage dividers" for multiple AC sources

Say we have two AC sources in a circuit. Is it possible to create separately control the output coming from each source using voltage dividers? (No op-amps) E.g. So that you have $$V_{out}=aV_1+bV_2$$ ...
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1answer
564 views

HVAC fan relay intermittently sticks closed; opens when touched

I have constructed a simple OR gate using two HVAC fan relays to control a 120VAC/1.5A booster fan for my home HVAC system. I have a zoned system, with multiple thermostats, but only one zone/...
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2answers
78 views

Using ADC for the first time, not sure how to choose a microcontroller for this [closed]

I have a 300 kHz signal with 5Vp-p; therefore, I would like to use LTC2315 which is 12-bit and has a sampling rate of 5 MHz. Reading the datasheet, it mentions that it uses SPI. My question is how do ...
2
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1answer
418 views

How to determine the right trip point of thermal cutoff for 1/4 hp 3A 115V single phase ac motor

The Thermal fuse blew in my Ryobi DP102L drill press motor, while I was drum sanding. There were no markings on the fuse. The single phase induction motor is 1/4hp 3A (no load) 1750rpm on 115V AC, ...
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1answer
322 views

Superposition and average power dissipation

Unfortunately, I am having trouble getting started on the question above. How can one model the affect of a voltage source on a circuit without the knowledge of the resistor configuration inside the ...
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2answers
77 views

Understand the calculations in an RC circuit - voltage division to polar form

I'm missing some calculation steps in an AC RC-example, and I can't understand how to get to the next step. If someone could show me, I'm sure to understand the rest. Example: A standard RC-circuit. <...
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2answers
225 views

Circuits of AC - impedance

I have a question regarding impedances. While it is intuitive that \$ R \$-element has impedance \$ R \$, it's not so easy for me to figure out impedances of \$ L \$ and \$ C \$. Here is my, probably ...
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117 views

How to keep a 220V bulb on using 3 phases simultaneously?

I a looking for a way to keep the bulb (5 watts max) on in case that any phase will disconnect. No relays(including solid state) or mechanical components are allowed for that. The best case will be ...
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5answers
2k views

Measuring 230VAC 50Hz mains (EU) voltage with Arduino

I was wondering if I could measure AC mains voltage with Arduino. The design uses a transformer to transform from 230 VAC to 12 VAC. Then the voltage is stepped down by the resistors. Arduino measures ...
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6answers
2k views

Isolated audio without a transformer

I'm putting together a guitar pedal for splitting the signal to two different amps. One of the features I want to put in is a 'ground-lift'; isolating the signal to avoid ground loops between the two ...
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0answers
77 views

Occasional light flicker, how to find source of issue [migrated]

Scenario I have a 110V line in my kitchen with 4 LED lights and a toggle on-off switch (no dimmer.) The lights have steady power and everything behaves normally EXCEPT there is a one-time flicker of ~...
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1answer
41 views

Generator data for synchronizing

I have two DG sets which are to be synchronized on to the same AC bus and needless to say, they must share load. I have gathered some parametric data which I felt would decide how well these can work ...
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2answers
176 views

Understanding the effects of frequency on appliances

Recently I was thinking about a generator project and realized that is beyond my current understanding of AC power. I have been doing some research since but I am really having a hard time ...

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