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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2answers
39 views

How to automatically switch to backup power?

To solve the frequent power outages that happen where I live I ended up using a spare car battery I had and a power inverter (one of these). With that I have more that an hour of backup power so it's ...
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0answers
35 views

AC fan speed control (using Arduino)

I wanted to control a 220V, 50Hz AC ceiling FAN using PWM output from an Arduino microcontroller and I have referred to several resources regarding this. Resources I referred ...
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1answer
29 views

Measure inductor coil's resistance using multimeter

simulate this circuit – Schematic created using CircuitLab Above is the set-up of my simple experiment to determine the inductance of an inductor. The voltage across resistor R (5 ohms) ...
2
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2answers
66 views

Is it possible to change the speed of an AC motor(drill press) without losing too much torque?

I have a drill press as in the image below, it runs from 110V AC 60Hz and has internal belt reduction. Unfortunately however for some materials and hole widths, I need it to go even slower than It's ...
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2answers
25 views

Calculate rotor slip without knowing synchronous speed

I am given the rated values of a squirrel cage induction motor: A 300hp, 2300V, 3‐phase, 60Hz squirrel‐cage induction motor turns at a full‐load speed of 590r/min. What is the approximate value ...
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1answer
44 views

Live wire , neutral wire confusion

I read that current enters an appliance through live wire and leaves through the neutral wire.Consider the appliance to be a light bulb.Now my question: 1.Shouldn't the current first travel to the ...
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1answer
94 views

By touching neutral why we do not get shock?

According to Benjamin Franklin, current flow from +ve to -ve terminal. But after Joseph Thomson's discovery it was conceived that although current flows from +ve to -ve electrons flow from -ve to +ve ...
2
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2answers
59 views

33V residual AC voltage in domestic circuit when switched off? Neutral switching?

I have searched Google, but get bombarded with "RCD" type answers. I read a few answers here that may have been relevant but turned out not to be, so I post my question. Being my first, I may ...
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1answer
54 views

How can a remote-controlled (wall) light switch operate without a power source?

A few days ago, i bought this remote-conrolled light switch. When installing it, i wondered why i had only two lines to connect (the one going to AC power and the one to the lamp); i thought i needed ...
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1answer
76 views

77V between Neutral and Earth (Single phase 230V/50Hz, India) [closed]

Normally in our 230V power outlet, the voltages are as given below. Neutral to Earth - Less than 2V Neutral to Phase - 200V to 230V Earth to Phase - 200V to 230V But nowadays, after around 10 am, ...
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0answers
27 views

what is the physical meaning of current lag voltage? [closed]

![enter image description here][1] [1]: http://i.stack.imgur.com/7lSui.gif wasffghuii
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1answer
23 views

Write V_final in terms of V1

simulate this circuit – Schematic created using CircuitLab Being \$V_1=10\sin(100t)\$ and \$V_D=0.7\$V, it is asked to find the output potential as a function of \$V_1\$. I made: ...
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1answer
38 views

How is low starting torque of asynchronous AC motors addressed when driving elevators?

Long before variable frequency drives became popular elevators were often driven by dual-speed asynchronous AC motors. Switching speeds was done by changing the number of poles (which is done by ...
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1answer
53 views

Water conductivity measurement AC, interfacing with arduino

I want to implementate this device, mentioned in the title. The problem is how to correctly build the " read out device" that is clearly a wheatsone bridge? But in AC, the problem is the signal ...
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0answers
24 views

modeling AC resistance proximity and skin effect using LTSPICE

I'm designing an air-core loop receiving antenna from <1Hz - 50kHz. Is there a way to approximately model the skin/proximity effect using lumped circuit parameters in SPICE software? I think you ...
1
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1answer
26 views

AC voltage source - variable load

I'm looking for some kind of idea for controlled load for AC source testing. The output signal of source is a bipolar sine wave 5 Vpk (so it varies from -5V to 5V) and it has 1.5kOhm series ...
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0answers
17 views

Where can I find the ac voltage in this diagram in LTSPICE software?

Where can I find the ac voltage in this diagram in LTSPICE software? Secondly, which settings in this software do I have to make to get alternating INPUT voltage just like in the diagram? What ...
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0answers
42 views

different voltage input on a transformer used as output

I have a transformer which I Take from my bridgeport milling machine panel box,I am thinking to make a phase converter and need 380v from my 220v single phase supply. this is the diagram of the ...
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1answer
74 views

What happened to my second half cycle of my half wave rectifier?

When I'm doing a simple half-wave rectifier with the set-up as shown above (Note: Diode D2 is not connected) and connected terminal 5 and 4 with positive and negative terminal of oscilloscope, this ...
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1answer
44 views

AC - DC Power Supply Non Isolated

I have been thinking of using LNK305P from Power Integrations to integrate an AC -DC power supply in my next project. The application note containing the circuit is here. What things do I need to ...
0
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1answer
56 views

Possible to take 110 down to safe level to run LEDs?

I'm working on a lamp project that I found online. It's a DIY lamp with a whiskey bottle for the base. The project itself just uses a standard 110V plug that goes right in to the wall, but I wanted to ...
0
votes
3answers
93 views

220VAC to TTL converter

I'm building a circuit that sends TTL level signal to uP whether AC signal exists or not. The schematic is as follows: Actually, the circuit almost works as I expect; however, there occurs some ...
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0answers
20 views

How do I power / control a brushed 115V AC motor?

How do I power a brushed 115v AC motor? Would there be any potential damage from just wiring it to just plug into the wall or do I need a transformer and a capacitor or something? Thanks!
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1answer
42 views

How to use an oscilloscope with a function generator?

I am taking a digital electronics class and I am utterly confused. I am using Multisim to design circuits, and for one of my labs I had to use a function generator with a oscilloscope. Here is a ...
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2answers
55 views

Real time digital audio frequency changing device

I want to make a device, which takes an AC audio signal like a guitar pickup signal, or piano or what have you as input, and changes the pitch using this function: ...
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2answers
149 views

How would I convert a 4.1(ish) volt li ion battery to 240v ac?

I'm fairly interested in electronics but not very educated in it. I was wondering how I would go about safely converting your average li ion battery pack to a usuable voltage (240v ac) for things ...
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1answer
34 views

shifting ac signal

I have an AC signal that is in the range of 1.5v-6.5v and it needs to pass through a buffer with a single supply of 6v to ground. So in this case, it needs to be shifted down by about 0.5v so that ...
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1answer
60 views

Transformerless rectification is giving out AC component [duplicate]

I want to convert 240V AC 50hz to 12V DC without transformer.I want the output (12V) to drive 25 white LEDs.The circuit is giving an output of ~14V DC.But the problem is that it is also giving out ...
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1answer
39 views

Is Deuterium arc lamp a AC or DC light source?

I have created a prototype photo-detector circuit to use in spectroscopy. The micro-controller code take 120 A/D readings and then returns average. I have noticed that when I use visible light ...
0
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1answer
57 views

What is the purpose of an inductor on an incoming AC line?

I am trying to build the following schematic. It is a AC/DC converter from Cui link I do not understand the function of L2. What is its purpose? I am having a ...
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0answers
58 views

What can I do to make this output usable electricity?

I built a generator having this output,the test load was 47 ohm, output reading was almost the same when on AC or DC setting on the millimetres. The generator was built with one goal, to generate ...
0
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1answer
49 views

How to supply 5 to 12v amplifier LM386

I started electronics recently and I'm trying to make the most basic mp3 amplifier. First I tried to make the amp myself with reused electronic parts but I didn't succeed... Amplify speaker with 9v ...
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1answer
18 views

Wattmeter Required for Transfomer Characterization?

I have to characterize and test a small 6VA 230VAC Transformer. Seems like I will do 1) Winding Resistance Test - DC Test 2) Open Circuit Test 3) Short Circuit Test I do not have a wattmeter, ...
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3answers
91 views

“Efficiency” of Switching Power Supplies and Theoretical Energy Loss

I have heard that switching power supplies that convert, say, 110 VAC to 12 VDC, are very efficient. I understand that the power transistor that is regulating voltage is either on or off and spends ...
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1answer
49 views

Is there any way to use an ac load ssr with a dc load

i have a s202s01 relay that i want to connect to my microcontroller. The problem is that the load i want to control is a DC source. Is there any way to make that ssr (3-24dc, 8A 250VAC) work with a ...
0
votes
1answer
45 views

voltage range of ac signal

I have an ac signal in the range of 1.5v-10v and it needs to be shifted down by 0.5v so it is in the range of 1v-9.5v. How can i do this exactly? assuming it uses a single power supply. any help ...
0
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1answer
70 views

Help Identifying Capacitor

I was given the following capacitor by a spare parts shopkeeper when I asked for a polypropylene capacitor (to be used in RC snubber circuit for a mains load). Can someone confirm this is the right ...
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6answers
190 views

Why does electricity have a phase?

Anyone who's seen the j in electrical formulas knows that electricity has a phase component as well as a magnitude. But where does the phase come from? Does it only ...
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0answers
47 views

Inverter vs Rotating Machine

My question is in how to relate a 3 phase PV inverter to a classical rotating machine. How is the machines power angle realized by the inverter? In power flow studies, real power flows by ...
2
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1answer
71 views

Must this switch be turned on and off periodically?

Imagine that the AC1-2 is 170VAC at 150kHz~. I simply want to turn the MOSFETs on, and let the AC flow through a inductive-capacitive load. 1) If I can turn the MOSFETs on to saturation by ...
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1answer
40 views

AC rms value of pulse train vs RMS value

I have a pulse train with Duty Cycle = 1/4, that oscillates from 0V to 3V. I found the RMS value to be $$ RMS = V \sqrt{D} = 3 \times 1/2 = 1.5 V $$ The DC offset, since it's oscillating from 0V ...
1
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1answer
48 views

Bootstrapping a bidirectional MOSFET switch?

is it necessary to use a driver and bootstrap circuit in order to make this configuration work; Or can I just stick 10V in it like shown? This is to make a bidirectional switch, I'm not pulsing ...
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0answers
78 views

Regulating Minimum Voltage

Is it possible to construct a circuit that outputs a voltage of 0 below a certain threshold , similar to a Schmitt Trigger, without using op-amps? In my circuit I want to prevent input voltage below ...
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0answers
36 views

Switching 150kHz mains for an LC load

I'd like some input on whether or not to use a mechanical relay or some form of SCR setup to change the capacitance in my LC circuit that is currently operating at around 170V, 1A at 150kHz. (Not ...
1
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1answer
49 views

How switch 20A AC between 2 wires

I'm trying to translate a circuit I made from breadboard to PCB and need some help finding out what components I should be looking for. Basically, so far I have a very simple circuit running 12V AC, ...
0
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1answer
59 views

How to amplify a small AC (no DC offset) wave with an op-amp powered from a 0-5V rail and a pot-varying gain?

I'm having a brain hiccup and can't figure this out. I've tried using simple summing amplifiers where I add my wave to an offset of 2.5V and then High-pass the offset. However, I need to be able to ...
0
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3answers
54 views

Switch current rating AC vs DC

I'm looking for a high current DC switch (able to switch something like 5V@30A) and I've encountered several DPDT that might do what I need, however they are only rated for AC applications (3A@250VAC ...
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2answers
66 views

Change AC signal frequency without changing the voltage

I have a non constant -/+1 Volts to -/+7 Volts AC audio signal. I want to design a device that takes this input signal, doubles the frequency, without changing the voltage. So, the output voltage is ...
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0answers
55 views

Mechanical Relay Protection (Controlling AC mains devices)

Trying to make a ucontroller controlled relay to switch mains AC devices. It would have a type M plug on one end(to plug in mains socket in the wall) and type M socket on other end(to plug in the AC ...
0
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0answers
35 views

How can I build a comparator for AC?

This simple scheme to compare Vin1 and Vin2 does work for DC current, but how do I build a comparator for AC current? In fact I would like to compare the RMS values. The purpose of the comparator ...