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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Possiblity of Using Transistor as Resistor

I would like to know it if is posible to use NMOS transistor to act as a resistor with a sinusoidal power supply ? The circuit I have is very simple; it consists of a 20Vpp-sinusoidal source ...
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2answers
64 views

How to estimate the maximum current provided by a transformer?

I have a transformer that outputs 14.3V (AC of course) and the current in short-circuit is about 13A (made a beautiful spark when I measured it :) ). Can I guesstimate from here what is the 'normal' ...
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1answer
97 views

Why am I getting electric shock from 12V DC Adapter

May be this is a weird question. But I am little curios to know why my 12V DC adapter is giving shock when the circuit is complete. I purchased couple of these 1 AMP 200V AC to 12V DC adapter. ...
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2answers
33 views

AC to DC wall adapter circuit

I'm trying to design an ac to dc conveter (230V ac to 12V dc). Haven't decided on the current yet. It's likely to be around 2A. I want the circuit to be compact and hence I think it is best to follow ...
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1answer
54 views

AC Voltage to Spark Plug

To get a spark plug to fire I read that it requires approximately 12,000 Volts. If I have an ac generator giving a RMS Voltage of about 10 Volts (pretty small) what do I need to do to get the spark ...
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37 views

How to build 5W LED bulb circuit from 230V 50Hz main AC supply with and without Transformers? [on hold]

Please answer with circuit diagram with all values or give me the link.Tell me the efficiency also. Thank u...
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2answers
64 views

Converting 2 pin plug into a 3 pin grounded plug [closed]

I have a portable power socket that accepts two 2 pin power plugs and 1 pin 3 pin grounded power plug. There is a hole on one side of this portable power socket where the wire goes into. Oddly this ...
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2answers
78 views

What happens to a normal transformer when the frequency is increased and the sine wave is changed to rectangle?

What happens if I grab a 220 sine wave 60 Hz transformer with an output of 12v if i feed it with a 220v square wave? And what happens if I increase the frequency? Like 100 Hz? And if I grab the ...
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1answer
43 views

ACS712 for high voltage

Is is possible to link an ACS712(http://www.alldatasheet.com/datasheet-pdf/pdf/168326/ALLEGRO/ACS712.html) module to a 220V electrical socket? I can't say if the module is built for low or high ...
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1answer
42 views

how to measure ac motor with AC ammeter

I have 3 different working motors ranging from 1kw to 2 kw (on 220V AC, 1 phase), they all use running capacitors. I tried 2 different AC ammeters on them and I get bad readings between 0 to 1 amp, ...
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0answers
53 views

how to protect h-bridge in a tig welder?

I live in Argentina and I was scammed with a Tig AC/DC Chinese welder, and the official lusqtoff service stole me believe it or not, and with the restriction to imports its impossible to buy a decent ...
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0answers
50 views

Adjust output offset of a Signal

i am trying to develop a signal generator which can have sin and rectangular signals . Another requirement is to adjust offset to +-1V.Here comes the question . I have finished to adjust + offset by ...
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0answers
44 views

AC Resistance Measuring Circuit

I'm trying to create a project to measure a resitance using electronics and a MCU ADC, and i'm having serious doubts about it and i could use some advices. My first two contrains are that the measure ...
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1answer
51 views

What does an “ac coupled signal” mean?

I've heard this term many times from many different sources, but none of them gave me a definition. Here is my understanding: "coupled" means "connected together". If two circuits are "capacitively ...
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2answers
50 views

AD620: AC Input Generating DC Output

I've been using the AD620 to offset and scale up a tiny AC signal for my project. The AD620 is set up in the following way: Rg= 6.8kOhms (between pins 1 and 8) Vin = 0.123V rms AC signal (pins 2 ...
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1answer
43 views

Multiple channel independent AC dimmer using Arduino

I want to build a 8 channel, independently controlled AC dimmer using Arduino. I have successfully tested a single channel dimmer but i am stuck in expanding it to 8 channels. The circuit I am ...
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0answers
20 views

Ceiling Fan is very slow after 2 years operation [migrated]

I have a ceiling fan is working with very slower speed even selector is set to the max (5 speed) and what is the reason for that ? Is the reason damaging capacitor or any other reason ? I just ...
0
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1answer
44 views

Transformer secondary wired to primary and secondary of second transformer

simulate this circuit – Schematic created using CircuitLab I see something like this for ethernet, and it confuses me. What is it for? What does it do? Could I remove that from the schematic?
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1answer
60 views

What is the correct way to add a direct voltage and an alternating voltage

Below I have two schematics that add two voltages (one direct, one alternating). Added to that, the both the AC and DC signals are going through voltage divider, but that isn't important. I'm ...
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1answer
71 views

Current flow through inductor (large inductance) in AC circuit

I fail to understand why does the current flow in one direction only initially at t=0 in an AC circuit.. also when inductance is increased the time take for the current to stabilize and move in equal ...
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0answers
21 views

AC circuit analysis

I need help with the following problem: Given the circuit of sinusoidal current (attachment 1) with given data: $$\underline{Z_3}=200(3-j4)\Omega, \underline{Z_4}=100(3+j20)\Omega, \underline{Z_5}=...
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3answers
51 views

DC rating for specific AC rated relay

I am interested in buying a high amperage relay which is AC rated (https://www.panasonic-electric-works.com/cps/rde/xbcr/pew_eu_en/ds_61A04_en_dqm.pdf). In particular it is rated for 60A @ 240VAC and ...
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2answers
116 views

Can we feel sinusoid? [closed]

If we have a signal of 1 or 2Hz, can our skin receptors feel that sinewave, if that sinewave has aproppriate voltage level?
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0answers
59 views

AC circuit problem

I need help with the following problem: Given the circuit of sinusoidal current (attachment 1) with given data: $$\underline{E}=100V,\underline{E_1}=40V,\underline{Z}=(10+j10)\Omega,\omega=10^5rad/s,...
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0answers
84 views

Identify This Connector (Polar Bear Water Distiller)

I am building an automatic water drain for our water distiller. The water distiller is a polar bear 26-D8. The company is basically out of business and is no help. The distiller has two connectors on ...
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1answer
106 views

Plugging in USB device shorts out USB hub

My device is 12V DC and takes a maximum to 1.08 Amps. The cable is split where one end goes into power and the other end goes into USB. Works: Plug device power into 120V AC adapter which converts ...
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0answers
27 views

RMS current of a circuit driven by a white noise voltage source

Note: I am an applied mathematician, not an electrical engineer, so apologies if this comes across as silly. I am analyzing the following circuit as part of some modeling related to energy storage ...
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2answers
49 views

Equivalent “capacitative reactance” for calculating rms current under mixed-frequency AC voltage waveform

I want to analyze a very simple circuit subject to a not-so-simple driving AC voltage waveform. In particular, my circuit consists simply of a single capacitor with capacitance \$C\$ and an AC voltage ...
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4answers
145 views

Detect AC current in series with load

I have a challenge at work to build a device to monitor the health of ceramic cartridge heaters, similar to this. It operates with an AC transformer and there are 5 heaters I'd like to monitor ...
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3answers
92 views

How to switch separate circuit from doorbell?

My doorbell rings as long as somebody pushes the button. I measured 10V AC at the bell when it is ringing. Now I would like to use this AC voltage to switch another circuit. How can I achieve this? ...
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2answers
29 views

Phasor math for balanced 3 phase circuit

Are there any mathematicians in here? I am currently reading my ECE text's chapter on AC machines and i referred to some material in the chapter that first discussed AC circuits. In the photo below ...
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2answers
67 views

Use of 230VAC overcurrent protection for 24VDC circuits [closed]

Is it right to use 230VAC overcurrent protection for 24VDC circuits? Why? Why not? For example: http://www.tme.eu/en/details/a9f05120/circuit-breakers/schneider-electric/ I saw some machines which ...
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2answers
50 views

What happens with voltage phase on the resistor and capacitor in AC circuit?

I'm currently studying AC circuits and I find it difficult to understand phase differences between voltage and current on different components. For example, let's look at this circuit: And here is ...
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1answer
51 views

An SPDT switch using TRIACs

I need to design a circuit that implements an SPDT switch using Triacs and Optoisolators. Currently I am implementing this with two pairs of Optoisolated Triacs with one having inverted signal from ...
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2answers
43 views

Am I correctly concluding that these two AC/DC adapters are interchangeable [duplicate]

I'm in the US with 120V mains. I have a "heavy" style AC/DC adapter (weighs a pound or so) and a lighter one (weighs a couple of ounces) which came off a 1TB Seagate NAS. Can I replace the heavy one ...
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1answer
96 views

How do I stop coiled (telephone) wire blocking signal?

This circuit is working just fine if the output signal uses a straight wire, even if it is a very long wire with say a 1K resitor added to the end of it. However, the signal does not get through when ...
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1answer
65 views

How can I create two ac signals with a voltage controlled phase offset?

Is there a fairly straightforward analog circuit (resistors, capacitors, transistors, etc) to generate two sine waves of the same frequency and introduce a relative phase offset between them? So I'm ...
0
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1answer
39 views

Interfacing a mains referenced AC measurement circuit with a PC

I need to connect an AC mains referenced measurement circuit with a notebook and I wanted to know if its safe to do that without an isolator. The measurement circuit primarily steps down AC voltage ...
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0answers
35 views

Energy meter measuring AC power

I am investigating building an energy meter probably using an Arduino and trying to understand the main principle of operation. We have a solar installation on our roof and already have meters for ...
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1answer
49 views

When calculating the voltage in an AC Circuit, I get a different angle from the correct answer

Problem I'am trying to calculate v2 from the circuit below, but my answer, 9.81cos(1000t+166.64°) mV, has a different angle from the correct answer, 9.81cos(1000t-13.36°) mV. My approach I tried ...
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0answers
61 views

How to wire capacitor start ac motor

I have a motor with a blue, yellow, black, and orangish wire coming out of it and I'm trying to figure out how that should be connected to power based on the wiring diagram on the side of this motor. ...
0
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1answer
39 views

How to wire this Buffton motor

I bought this motor at a scrap yard and would like to wire it up for 120 volt power. There are 5 wires coming from the motor, a black, white, ground and two yellows. One yellow is numberer "2" and ...
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1answer
74 views

Will a 0.5V difference in output damage the device? [duplicate]

I have a speaker adapter, with an output rating of AC 11.5V ~ 1600mA, which I am looking to replace and the only replacement I can find has a rated output of 12V ~ 2000mA. I've read somewhere that a ...
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0answers
69 views

Blower (Fan) Capacitor on Water Cooler

I've got a water cooler that has a centrifugal blower inside it. The blower fails to start most of the time, but I've verified that the motor works because it starts with a slight nudge. A slight ...
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0answers
59 views

Circuit to measure impedance

I'm trying to make a circuit to measure impedance through a FRDM-KL25Z board. The basic idea is to use two signals to calculate the phase shift between them, and use a impedance divider to calculate ...
0
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1answer
65 views

How to 'average' a sine wave of RMS values?

Lock-in amplifiers (Stanford Research Systems 830) display sine wave signals in RMS values SR830 Manual (page 3-3). One can use the internal buffer to rapidly measure a signal, storing up to 16000 ...
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2answers
106 views

How do I prevent backfeed through contactors when joining 3 x 230v ac circuits all single / same phase

I am working on a project to safely combine separate power circuits into one. Its to do with using available power instead of renting mobile generators. The problem is that the 'magic box' has ...
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0answers
27 views

Resonant RC Series and deriving equivalent circuit

How is it that this is equivalent? Assuming all transients have died out. vi = Vcos(omega*t) The fake input was defined as: \begin{equation} v_{cp}^\sim = \frac{V_i}{1+j\omega_1RC} e^{j\omega\\_1t}...
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2answers
46 views

Calculating true power of a predominantly inductive load?

I'm stuck at this problem, which doesn't seem to be so difficult, but, I guess there is some basic stuff that still confuses me. So, if we have a load represented with complex impedance \$Z=30+j40 \ \...
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6answers
100 views

Controlling the frequency of AC used to energize an electromagnet

I am trying to build an electromagnetic pendulum which essentially has a pendulum arm with a permanent magnet at its end which is 'kicked' by an electromagnet placed at the mean position to drive the ...