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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PSC motor driver circut using relay

I am working on a project in which i need to connect Permanent Split Capacitor(PSC) AC motor using relays as shown in the below block diag fig 1. I want to rotate it in both CW and CCW direction. It ...
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0answers
37 views

Variable Plug Outlet 110~120 VAC [on hold]

I have a lamp in my newborn son's room, and like many lamps, it's on/off switch makes noise, which he does not always like to hear when falling asleep. Do they already make some sort of TRIAC style ...
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1answer
89 views

AC voltage gets mixed with DC

I am using ATS (automatic start) for my generator. Its programmable IC goes out of work after 2 or 3 days and I have replaced 3 ATS card. My card supplier says that you are somehow getting AC voltage ...
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2answers
62 views

Lamp flickers if dimmed up to an extent

I used circuit shown in this instructable to make an AC dimmer but everything goes fine if not dimmed much but then it starts flickering because of voltage fluctuation. ...
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2answers
54 views

How to select most efficient motor for generator?

First post. Please forgive me if this is a stupid question. This post can be broken down into two questions. I am building a bicycle generator, but am new to the field of EE. I am trying to select ...
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3answers
55 views

Which is good method for step down 50Hz, 230V AC

Which is low cost and safe for step down 50Hz 230V AC into 12V? Transformer or reactance or Regulator IC ? simulate this circuit – Schematic created using CircuitLab
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2answers
84 views

Measure 230V mains with 300V CAT II probe?

I need to measure harmonic distortions on a 230V 50Hz AC mains circuit. The Tektronix P2220 probes I have for my scope are rated for 300V CAT II when set to 10X impedance. Are these probes safe to use ...
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2answers
67 views

Phase Shifter: why is simple RC circuit's output 0 when phase is 90 deg?

I am rereading an electronics book (Fundamentals of Electric Circuits; Alexander) that says that the circuits or have the total impedance Z = R + jXc and that the phase shift is given by ...
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1answer
41 views

Elements of an AC expression

I am doing some coursework and research on AC theory and currently exploring the below expression: $$V= 100sin(100\pi t) + 60sin(300 \pi t - \pi/2) + 30sin(600 \pi t + \pi/2)$$ I need to find the: ...
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1answer
28 views

Connecting 3 phase ac motor

As far as I understand in delta connection 3 lines and earth is connected to the ac motor. But if wye connection should one use the neutral or earth to the motor?
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3answers
61 views

SPDT Relay with 8Pin

I needed a SPDT relay with 240Vac so I bought this relay from Maplin http://www.maplin.co.uk/p/15a240vac-spdt-miniature-relay-n07aw But I am heaving problem to wire this relay because it has 8 pins ...
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2answers
146 views

Using a shunt cap to create a delay - good idea? [closed]

simulate this circuit – Schematic created using CircuitLab C1 is a decoupling capacitor. If the input of U1 is experiencing undesired phase shift, can a decoupling capacitor correct the ...
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1answer
41 views

Bidirectional AC Switch with IGBTs

I came across a "IGBT Bi-directional Switch" on the web while looking for a solution to my problem of protecting a TRIAC/SSR from a short-circuit. Since TRIAC/SSR turn-off is not in my control, I'm ...
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2answers
91 views

What wattage solar panel required for AC 1000 watts

If my house load is 1000 Watts AC/220V, then 1000 Watts DC/12V solar panels is not enough. What wattage solar panel would be required for AC 1000 watts?
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3answers
461 views

How many Watts DC are equivalent to 1,000 Watts AC? [duplicate]

How many Watts DC are equivalent to 1,000 Watts AC? For instance, my load in AC is 1,000 Watts 220V. Then, how much DC watts would an equivalent load dissipate in 12V or 24V DC system?
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2answers
94 views

1n4007 Bridge Rectifier at 220 Volts AC?

So, I just started getting into electronics, and I have built a bridge rectifier using the 1N4007 diodes. So far I have been using this rectifier with a 24 volts step down transformer, but now I need ...
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5answers
2k views

What happens if a 240V appliance is connected in a 120V AC power supply?

I know that putting 240V through an appliance rated at only 120V would almost certainly damage it. But what if I connect an appliance rated for 240V into a 120V AC socket? Apart from degradation in ...
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2answers
37 views

Finding the non-zero value of ω, such that V and I will be in phase

Consider the impedance network connected to an AC voltage source in Fig. Q3(a). i) What is the network's equivalent impedance, in terms of ω? $$ ...
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4answers
78 views

Triple pole triple throw relay

I have a turntable which rotates cw and ccw. This turntable is rotated by AC synchronous motor of 230V. I want to be able to rotate the turntable with Arduino. For this reason I need to control the ...
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3answers
557 views

What is this AC source?

Below is a part of a schematic and I would like to understand each part of it. What I think is happening: This is being fed a 48V AC source These leads are a source and a ground? I'm not sure ...
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1answer
98 views

Running brushed universal motor at different frequency than designed

First, the end goal is to run a power tool (namely a Dewalt DW734 thickness planer) designed for 110V at 60Hz at a country where the power is 220V at 50Hz. The motor is a brushed universal motor, ...
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1answer
44 views

DC motor spun clockwise then counter clockwise creates AC current?

I am making a generator with a DC motor but the style of turning the rotor would be clockwise and then counter-clockwise, and I would want to capture as much current as possible so I hope it could be ...
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2answers
87 views

AC amplifier with fixed output range?

Lets say I have a sine frequency sweeping circuit (1kHz-10MHz) that goes down in magnitude, from say 3V to ...
2
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1answer
73 views

Device to switch a 220VAC/40A resistive load

I need to switch a 220VAC/40A resistive load. I only need on/off switching, no phase control. I would like to avoid mechanical (moving parts) components if at all possible because of reliability ...
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0answers
88 views

Mosfet as a Switch

I have created 2 circuits using altium designer as shown below: After simulation here is what i have for the left circuit: Right circuit: Basically, as you can see in the first circuit i have 2 ...
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0answers
35 views

LED bulb that works on both 64 volt DC and 110 AC

Can anyone advise on a reliable/cost-effective way to modify a screw-in LED light bulb so it will run on an AC power supply that has a battery backup where DC is provided in backup mode (this is for ...
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1answer
100 views

What capacitors do when it is connected in Series and parallel to a AC input

I have seen in many circuits the capacitors are connected in series and parallel with the AC line. What the capacitor actually does when it is in series and parallel. I know capacitors passes AC ...
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4answers
366 views

How can a faulty USB charger kill you?

This question relates to this incident here. Where a women in Australia died from a faulty USB charger that allowed the full 240v mains voltage through the USB cable. Now from my understanding you ...
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3answers
77 views

Stable power for LED from 5.5 to 7.5V AC

About a year ago I posed the question "Making 12V DC from 6V AC". Since the conversion from AC was going to be problematic (for me), I tackled the tail/brake light first, because working with the 6V ...
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1answer
63 views

Question on capacitive circuit in practice

If we were to build a circuit, let's say with a power source of 120V AC going into a transformer which steps that up to 10kV @ 30mA, the output of which would be connected to a capacitor with a ...
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1answer
86 views

High voltage/current design on PCB

I am building a circuit that allows me to control a set of light (more specifically Christmas lights you see in supermarkets) with relays (AQH 2223). My idea is to have the controller input on one ...
3
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5answers
280 views

Why do electronic circuits need their power supply to be DC, or rectified AC?

I'm pretty sure the answer to this should be obvious - even to me ... It's been a while I've been reading and attempting to construct simple electronic circuits. The supply almost always is either ...
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1answer
81 views

Why would we need to ground an AC source?

I'm new to this field hence this weird question. Why would we need to ground an AC source? Why wouldn't it be enough to have just one pole to get an AC current going? I understand why it wouldn't work ...
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2answers
68 views

Can I make pulsing light using AC as source, a diode and a LED?

I'm new to this branch of physics hence my stupid question. I know that diodes are used to make current flow in only one way. If I connected an AC source to a diode and the diode to a small light ...
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1answer
84 views

Way to measure AC power in 2 wire cable

Is there a way to measure AC power/current delivered through 2 or 3 wire cable? I know that from Ampère's Law the total current of both wires is zero, but is there a way to measure power in cable in ...
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3answers
121 views

What is the deal with resonant frequency?

During the last day or so, I have studied the topic of resonant frequency over a few circuits. Now, I could easily see that every time my circuit operated upon that resonant frequency something ...
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1answer
113 views

220V AC power cable max current

I installed 1mm2 copper AC power cable across house for video surveillance (8 cameras, Power Consumption for each camera is Max 4W, 12V). For each camera has its own 220V->12V converter rated 3A. ...
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2answers
130 views

How can I add three AC signals?

I have three light sensors which outputs appropriate AC currents with respect to light intensities. I only have one pin left for my ADC IC that I have on my board so I can't sample three sensors using ...
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0answers
67 views

DC Voltage of a 12V AC transformer after rectification

I want to drive relays using Method 2 of the following question: What is the most economical way to drive an array of single coil latching relays? This basically means that any time the relay is ...
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1answer
65 views

Is it possible to power an AC-to-DC switching adapter with a DC input?

Typical "wall-wart" switching power adapters are often rated for ~110-240V 50-60Hz AC input and output low-voltage DC. For this question let's assume the output voltage is 5V DC. Internally, the ...
2
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1answer
158 views

Does the polarity of my AC adapter match that of the device? [closed]

Looking at the symbols, I think the polarity matches the adapter and device (tip positive), however the design of the symbol is different which is is confusing me, so I want to be 100% certain that ...
0
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1answer
81 views

Connecting ON/OFF switch

Forgive me for the simplicity of this question but I am a microelectronics/very low voltage guy, and I have only 1 switch so I want to get it right the first time. Better safe than sorry :) I have an ...
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3answers
96 views

DC or (AC + DC) coming out of a full wave rectifier

DC or (AC + DC) coming out of a full wave rectifier Is there a truly correct answer to this? Considering the representation as a waveform I would say its an AC wave form offset by some DC amount. ...
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7answers
1k views

Why are rectifiers-inverters used to drive AC motors instead of using the rectified current to drive DC motors?

I understand the advantages of using a rectifier-inverter system to drive an AC motor instead of simply plugging it into mains power, as it allows much better control of its speed and performance; but ...
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1answer
60 views

Calculating the current of an AC circuit

My goal is to calculate the current i(t) up in the right corner. Using the formula $$ Z_{total} = \left( U\over I\right), I = \left( U\over Z_{total}\right) $$ Given values are $$ R_{1} = 1k ...
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2answers
100 views

Switching between AC and DC input

Let's say I need to power a 9v device with an input power source that is either AC or DC and changes almost randomly. Is there any way for me to detect in a circuit when AC changes to DC or vice-versa ...
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3answers
75 views

How to calculate average voltage from a series of discrete points

I require the method to calculate average voltage from a series of discrete points from an AC waveform. Everywhere I look the answer is Vavg = Vpk * 0.637. I understand that this works for a perfect ...
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2answers
97 views

How can I make a 5mm LED rope using 6v transformer [closed]

I want to glow LED using a 6v AC transformer. I want to add 18 color changing leds (5mm) as series. I cant add too many wires through the rope (pipe). See my plan: what are the components I ...
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1answer
96 views

How can I make a LED rope using mains (AC power) [closed]

I want to glow LED using AC power. How can I add combine multiple LEDs to make an LED rope? Versions that I would like to build are: 18 x 5mm LEDs 20 x 10mm LEDs Mains voltage here is 220 V AC ...
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1answer
101 views

How can I make AC powered 5mm LED string? (with more than 16 LEDs) [closed]

I want to make an AC powered 5mm LED string. I searched a lot but I never found a working one. I just tried one experiment from the Instructables site. But when I connected it to AC power, one ...