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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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67 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 ...
2
votes
1answer
101 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
51 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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0answers
23 views

AC & DC Voltage source superposition theorem

My professor mentions in his notes that the voltage of v is 5 Volts at the capacitor However, I tried using nodal analysis on paper and my answer matched with the voltage shown by my simulation of ...
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3answers
81 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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0answers
29 views

DC-AC circuits exercises [on hold]

I have some problems with electronics and I can't solve the two exercises below: the first one: and the second one: In the second exercise I managed to calculate (hopefully it is correct) that DC ...
7
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1answer
473 views

Identify Vintage Power Cord for 1980s Organ [on hold]

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
13 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
31 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
30 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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0answers
32 views

I need help in ac to dc variable power supply [closed]

I HAVE MADE A VARIABLE AC TO DC POWER SUPPLY 0-20V . I WANT TO MAKE IT FROM 5V TO 20V. HELP PLEASE AND DONT TELL ME TO USE LM317 OR ANY REGULATOR.
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0answers
19 views

AC sweep/noise simulation error

I have designed a simple audio amplifier circuit. When I ran the simulation with Time Domain Transient, it was able to produce a nice sine wave with about 20x amplification using the Vsin voltage ...
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2answers
64 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
82 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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0answers
22 views

How to increase current in AC synchronous generator

I have an AC synchronous motor how to increase the current generated by it by keeping the voltage constant.should I add more magnets
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1answer
30 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
54 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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0answers
25 views

AC signal for impedance meter design

I am designing an impedance meter with NI current output device and voltage input device. I am applying a current signal, measuring the voltage response and dividing Vp-p of voltage and current to get ...
1
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1answer
47 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
39 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 ...
2
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1answer
81 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 ...
0
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1answer
56 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 ...
-2
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4answers
89 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
53 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
80 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
50 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
58 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 ...
2
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3answers
109 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 = -...
-1
votes
1answer
33 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 ...
0
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1answer
48 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 ...
0
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4answers
89 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, ...
1
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1answer
29 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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2answers
74 views

High pass filter is not resulting as good as the scope's AC coupling

I'm generating sine waves by using a micro-controller and DDS module. The output sine normally swings always positive between 0 to around 1V. But I want to generate a real alternating sine with ...
0
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1answer
68 views

How can I build BJT amplifier with Vin and Vout requirements (peak to peak values)

I have been working on a project but I'm not sure if I'm complying with the requirements that I was given. Design a BJT amplifier such that VIN=0.1 V and VOUT=5 V (peak to peak values). ...
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2answers
34 views

Powering a mechanical (el. magnet) doorbell with an AC LED driver

I have an old fashion ding-dong doorbell that is powered by a 12VAC 1A transformer. The old transformer died and I decided to replace with a cheap AC LED driver which is rated 12VAC 50W. That didn't ...
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3answers
82 views

Amplifying high frequency AC using op-amp or alternative methods

Right now, for my project, I am trying to design a circuit for generating 10 kHz to 1 MHz AC signal with ~80 Vpp to 100 Vpp. Currently, I chose to the AD9850 chip for generating AC with Vpp being ...
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0answers
28 views

Light fixture still live when power turned off [migrated]

I'm sorry if this is an ignorant question, but it is one that I cannot seem to figure out. When I was changing a light bulb in my ceiling pot light fixture, the power switch was turned off, and I ...
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2answers
33 views

Protecting a relay/SSR when driving AC window cover motor

I'm having trouble switching an AC motor. Relays spark and glue contacts, and SSRs start to flicker and not pass the full input after a while. The motor has 3 terminals for 230VAC mains. One is ...
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0answers
28 views

Dimmable 120V AC LED bulbs intermittent brown out?

I have 5 dimmable LED light bulbs hooked up through a common fixture to a dimmer. Roughly every minute or so, the bulbs will dim in unison slightly for about 1 second, the come back up. I have ...
1
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1answer
34 views

Measuring 24V AC input state with microcontroller

I need to measure the state (on/off) of a 24V AC line that is currently powering a solenoid valve. The microcontroller will take over the control of the solenoid through a solid state relay, but I ...
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0answers
30 views

Unbalanced 3 Phase Load Power Calculation

I am having trouble calculating the power delivered by the voltage source with an unbalanced 3 phase load connected. See question in more detail below: Part (d) is easy with a balanced load but I'm ...
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1answer
21 views

Which suppresor device will be use for 2pole AC contactor 240v coil voltage in coil as well as contact side?

I need an AC contactor for a 1 hp motor. For the contactor safety I'm goint to use the suppression device on the both coil and contact side. Please suggest me which suppressor device will be use! I ...
1
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1answer
35 views

How Does Line Frequency Affect Coils of a Contactor?

I am using a generator as my source voltage, which produces 240VAC @ 240Hz. I was planning to use the following contactor from TE: CONTACTOR 4PST 40A 240V In the datasheet it says this contactor's ...
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1answer
90 views

Will an AC series motor work with DC supply?

I have read that a DC series motor can be operated using AC supply, but there will be excessive heating in the core and yoke and also a low power factor. So, construction is modified to have laminated ...
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1answer
55 views

One wire AC power

I would to connect a nodemcu board (powered by 3.3 V) to AC power behind the light switch, but I can use just one AC wire (the one that opens/closes the switch for light). Is it possible to do that ...
0
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1answer
50 views

AC motor turning a certain turns and stop, then can turns reverse only for certain turns

I bought this motor from some one who said it was used in an automatic recliner armchair sofa. The motor can turn only certain turns [set N] and stop, then can turns reverse only. It can resume the ...
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1answer
30 views

Finding the specific Turn Ratio of a Transformer

I'm finding the turn ratio for a Hammond 166G28 28VCT transformer. I already had calculated the voltages for the Primary and for the Secondary and I divided them and got 3:1 ratio for the outer loop (...
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1answer
89 views

If wind rotates my fan, will it cause electrical problems?

I'm planning on building a DIY dryer booster, using this cheapo 220V inline fan: I plan to connect it to a temperature switch and a fuse, and connect it to the exhaust of my dryer. (I'm doing this ...
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1answer
63 views

USB 3.1 AC Coupling Capacitor Implementation

How should the AC coupling should be implemented when connecting a USB 3.1 hub to a USB Type-C connector through a MUX. Is it: Both sides of each MUX. On the switched output of each MUX. On the ...
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1answer
55 views

How to calculate maximum amount of bulbs I can connect in parallel to match design specification of 1.5 A?

I'm designing a sensor triggered circuit that involves 220 V passing on a PCB, so I designed the board thickness to withstand a maximum of 1.5 A. The main load on the circuit would be a series of LED ...