Questions tagged [ac]
AC stands for Alternating Current. It usually applies to voltages with >100 V RMS, but can also be used for other AC voltages, like 24 V industrial AC power.
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Low-voltage lighting circuit switch - why does it not cycle constantly?
I have a low-voltage lighting circuit I'm trying to understand. Not an electronics guy, but adjacent.
I look at this circuit, and if I were to hold the momentary button down I would expect the relay ...
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How to wire a capacitor together with a Zigbee fan controller? Do I need the capacitor at all?
I bought this Zigbee ceiling fan controller:
product page
I started to wonder about what the purpose of a capacitor in a ceiling fan is.
This controller claims that it already controls the speed, and ...
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Floating relay terminal in AC circuit causing simulation error
I'm trying to switch between two branches for my circuit. But as the relay switches, the other terminal is left floating. In an AC circuit, I cannot use a pull-down resistor.
I also have a feeling ...
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Voltage difference between input and output of transformer [closed]
I have been trying to find the voltage difference between the input and output terminals of transformers, but every google result just got to the primary vs secondary so I decided I would just ask ...
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Power Electronics Exercise [closed]
Can someone help me solve the following exercise?
In English, parts a) and b) ask:
a) What is the value of "R" when we have a value of 10A as the effective current?
b) What is the average ...
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Capacitor can't filter the AC detector spikes
I made a simple design to read the status of an 220 V AC relay. I used a diode and resistor to drop the voltage for the PC817 optocoupler and used a capacitor to filter spikes:
This is the test ...
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Do I need to implement a DC Offset for this audio signal?
I'm using the TPA3137 Class D Amplifier to amplify an audio signal coming from a Summing Amplifier. The TPA3137 amplifier does accept differential inputs, but my intention was to use a single ended ...
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AC amplification [closed]
document link: https://www.zorgeffects.com/index.php/en/blog/33-tremoloo-ooo-ooo-ooo-ooo
How can I use this theory to amplify an AC signal? my project is run through a 5V supply hence the MCP601 rail ...
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Can I reduce these 3 ac adapters to one?
Scenario: I'm (for fun) designing/building an automated irrigation system for a greenhouse. There should be 3 solenoid valves, connected to a 4 channel, 5 volt relay, connected to a Raspberry Pi.
In ...
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Triac flickers when I apply main power
I am building an ESP32-based AC mains power switch by using TRIAC BT136-600D (common triac).
My first issue is my load didn't turn off the load (lamp) properly at 30%-40% brightness, and when triac ...
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Relation between power, voltage and current [closed]
I just started work in an industrial food manufacturing company, and they ask me what will happen to current if voltage increases in an industrial setting. I answer with OHM's law which state that ...
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Handling higher clamping voltage of IsoMOV - MOV/GDT Hybrid
I'm working on an ac mains control circuit and came across IsoMOV a new hybrid MOV/GDT for surge suppression. This appears to be a straightforward replacement for a standard TPMOV with additional ...
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Will back EMF be a problem when operating a solder fume extractor with a foot switch?
I have an Xytronic HV-2 solder fume extractor. Operating it is cumbersome since I have to crawl under my desk to switch it on and off each time. I'd like to add a foot switch for easy operation. I ...
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Confusion about AC current relative to frequency
Having trouble conceptually understanding why AC peak current (capacitor voltage = 0) is different between circuits where all variables are the same, except the frequency.
Looking at the pictures I ...
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Does transformer efficiency affect output voltage or current?
I have a list of basic problems. Let's suppose a textbook problem. A transformer has an efficiency of 93%.
We know the primary voltage and current. We know the numbers of turns and the efficiency.
The ...
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How to check the high voltage of a electrostatic device?
I want to build a device with two metal plates which needs to have 3000 VDC between them.
The way that I am thinking is to use a ferrite transformer from a 9 VDC transformer with a transistor that ...
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Discharging capacitor after power shutdown
I've got a simple circuit that acts as a 230V softstart:
It works, but there's one issue with it - after turning it on a 100uF capacitor is charged, and after turning off it is discharged by a 22k ...
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Determining the region of operation of these two diodes
I'm having trouble determining the region of operation for these two (ideal) diodes. Do I check the Vopencircuit values or their current values?
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Calculating input power of ACDC power supply
I'm trying to calculate the input power draw of an ACDC power supply that we are using in a control chassis and am confused by what to me looks like conflicting information in the datasheet.
The power ...
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Understanding difference of potential in an AC circuit
I have a circuit that takes 120 V AC fed into a transformer and puts out 24 V AC. The circuit uses a difference of potential to energize a relay and keep it closed using a holding circuit.
What I don’...
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Cause of Current Spikes at Zero Crossing in LC Circuit Connected to 50Hz Mains
I set up a simple experiment where I connected 8x680nF 450VAC polypropylene film capacitors in parallel across a 250VAC, 50Hz mains supply. The capacitors, nominally at 640nF each, have an equivalent ...
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Parallel RL-C circuit simulation to calculation issue
I have been trying to make some sense of a parallel AC RL-C circuit for over a week now.
The question asks "Measure the current and active power absorbed by a lamp (simulation circuit below and ...
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Would the inductor have an inductive reactance due to mutual induction via an AC source?
In a setting like that in an ideal transformer. An AC source connected to the primary induces an AC voltage in the secondary. Would the secondary coil have an inductive reactance in this process?
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Does RMS value of AC signal depend on frequency?
The formula for voltage RMS is usually given as the peak value divided by the square root of 2. I feel like maybe I am missing something: how can two AC signals with same amplitude but different ...
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Terminology: Proper way to denote typical European 3-phase AC grid
The widely known 3-phase grid in Europe with 50 Hz and 400 V between two phases and 230 V between each phase and neutral is often referred to as "3 x 400 V" or "3 x 230 V".
Is one ...
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Grid tie inverter 200 W with low voltage auto disconnect
I have a grid tie inver that produces at most any day 200 watts from my 12 V battery bank. I also have a adjustable auto low voltage disconnect circuit that disconnect the 12 V from inverter when ...
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Need help with AC relay wiring
Got the following relay Taiss/AC 220V (YJ2N-LY AC 220V)
A picture and a wiring diagram are below.
Given:
AC 230v constant L input
AC 230v signal L input
N input
,
How should I wire the relay to get ...
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What is the most efficient way to detect if AC mains is live for interfacing with a microcontroller?
I want to implement an electrical mains level detector to interface with a microcontroller the simplest and most efficient way possible as this circuit would always be on. I’m trying to detect when a ...
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Two X capacitors from lines to ground- why? GFCI fault, even after replacement
I'm trying to repair a very old printer (circa 1980). When I plugged it in, the GFCI outlet protection immediately tripped, even with the printer turned off.
The hot side of the cord is connected to ...
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Noise in DC supply due to AC track nearby
The RL_NC track in the image will carry 230V AC. Will the EMI noise from this track affect my 9V supply nearby (output of LM7809)?
I use the 9V supply to measure the voltage drop across a conducting ...
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Unstable to do resistance measurements due to electric fans
I built a small system to monitor wood drying. The idea is to turn on exhaust or circulation fans (230V-AC) based on the absolute humidity and ambient temperature (respectively) of a small drying ...
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Mixing audio signals: pros and cons of using resistors instead of an op-amp
I'm working on a project that requires me to mix two audio signals from two sources (both on the same PCB).
Source one is an audio output coming from the the VS1053B MP3 Audio CODEC IC, and source two ...
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ESP32 powered over long lines with 230V
I'm planning to put several Ethernet ESP32s with AMS1117 5 V to 3.3 V power converters and SHT31 temperature sensors around my house to report temperatures. They will be connected over Ethernet; power ...
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Fourier circuit analysis of a RLC circuit
I was trying to calculate output voltage across the inductor in the RLC circuit below. I had used the Fourier transform to convert input signal \$V_{i}(t)\$ which is a single rectangular wave pulse in ...
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Design review request : First AC design - Is this dangerous?
This is my first board with AC.
I'm planning on using it to power an ESP32. Overall the consumption will be much less than 0.3A.
I'm putting two HiLink HLK-PM01 units in parallel, with 0.3A output ...
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AC line filter polarity
Currently I working on very simple AC power mains distribution board. I want to use PCB-mounting AC line filter SCHAFFNER FN405-10-02 for EMI reasons. The datasheet provides simplified schematic:
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Is it OK to use a transformer as an AC power supply source?
I work as an IT specialist in company. The company acquired a used Axis 232D+ surveillance camera.
This camera is special. It requires a 24V AC 1.5A power source (as specified on p.48 here.) It was ...
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Brushed DC-Motor with Shunt Winding running on AC?
Why can't a brushed DC motor with a shunt winding (stator and rotor windings are connected in parallel) run on AC? As far as I understand it, the stator current should switch polarity at the same time ...
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Make a 0.5 HP, 3-phase motor work with single phase voltage with capacitor [duplicate]
I have a MGM Varvel's SM71B4 AC motor which runs on 3-phase that comes out of a Schneider Electric's VFD called Altivar ATV12H037M2. The VFD has failed and doesn't show the input voltage, so I decided ...
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Why do I measure a voltage between me and the hot wire?
If I plug one lead of a multimeter to the outlet phase wire and the other lead to my hand, why does it show 100 V when I stand in carpet, and 150 V when I stand at pure floor? What causes that voltage?...
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Sharing 115 VAC ground and 28 volt DC ground
I have been wondering if it makes sense to tie DC Power and AC Power ground like this.
Basically the AC return from an AC power supply is tied to the DC Power negative line as well.
Is there a good ...
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Real resistance at AC vs DC frequency?
I am using an LCR meter to measure the characteristics and impedances of various coil antennas. This LCR meter can measure both real and imaginary components of impedance at a certain frequency (R and ...
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What is this glass bulb containing three parallel electrodes?
I'm trying to figure out what the glass component on the PCB is. Maybe some sort of vacuum tube? Maybe a triac? It's got three leads, and appears to have three parallel electrodes inside the glass ...
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Is it possible to design an over/under AC voltage protection circuit using only diodes and SCRs?
Is it possible to design a circuit using only SCRs and diodes (Zener or otherwise) as a main regulating device to protect a load (220 V, 80 W) from over- and undervoltage? Other passive components (...
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AC delay circuit question
Sorry if it's a stupid question but.. is there any AC delay circuit? All I know is RC and RL circuits but are based on DC current
For example, to delay for a second the triggering of an AC relay
...
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What is the best way to convert 3ph 380VAC to 3ph 0V >> 450VAC in range of 800 kW?
I have a company that makes servo AC voltage regulators and some other transformer-based products, and today some of my customers asked me to give him a quotation for an 800 kW Variac, the biggest one ...
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Device to vary the AC voltage output and frequency
Can a function generator be used to generate signals from 120 V to 220 V with a frequency of 50 Hz or 60 Hz?
The issue is that I require these signals to test an application for a microcontroller that ...
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Capacitance displacement probe guard ring circuitry
I am attempting to build my own capacitance probe for high precision displacement measurements. The working principle is simple - a constant current AC signal (~100kHz) is passed through the probe ...
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AC air compressor voltage spikes [closed]
I have a "mgf compressors" named MINI BEV that generates voltage spikes up to about 500Vpk (353Vrms) on the 230Vrms AC lines. My question is if this is normal? I understand that its an ...
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How do you measure phase resistance and inductance of a three-phase BLDC motor without a DMM or LCR?
I need to measure the phase resistance and inductance of a BLDC motor using circuitry without multimeters. I'm not getting the the proper solution for this. Can someone help me out to get the solution?...