# 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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### Accurately Measuring AC Voltage

I’m curious to see if anyone has any experience on the accuracy differences in measuring 120V-277VAC in the following ohmic ways. In all cases, the voltage would be put through a voltage divider to ...
33 views

### Dual AC Power Input on Audio Amplifier Board

I'm confused as to what kind of transformer I should use to power this board. The manufacturer states the operating voltage as follows: AC12X2 to AC22X2. Should I assume a phase shift of 180 degrees?
223 views

### Is It Posible To Have Step Up Power Supply Without a Transformer?

I am trying to design a high voltage low current power supply. My purpose is to design it without a transformer. For example circuit like this : My input is 220V AC after this circuit I am going to ...
123 views

### How does “delta”-like three phase power source avoid short circuit? [duplicate]

A delta-like 3-phase power source is as below: simulate this circuit – Schematic created using CircuitLab This diagram is equivalent to "Fundamental of Electric Circuits, 5 Edition" Figure 12....
124 views

### Running a long 120VAC line without a neutral

Source is a home 120/240VAC with pole transformer. I want to direct bury a 500 foot 120V line to run some battery chargers and dont need more than 10 amps. Why cant I only run a single large ...
56 views

### Maximum Supply Voltage Output by Transformer - Sanity Check

First off, I am not an electrical engineer by trade, or even by education. Pretty much everything I know about EE is self-taught, and I know enough to make a hobby out of it, but may be missing basic,...
60 views

### Common mode inductance of a three-phase reactor

I have designed a three-phase differential mode reactor on a 5-legged core. I am trying to calculate the common mode inductance of this reactor. Does anyone know how to do this?
78 views

### Overvoltage protection Piezo Harvester

I have a piezo harvester, capable of creating spikes of 50+Volts. My harvesting circuit which will be connected to the harvester output, has a maximum rating of 20Volts. Therefore I need some kind of ...
49 views

### AC to DC converter device (AC adapter) with adjustable output voltage and adjustable output current [closed]

Is there a device available in the market that can take an input AC from mains and convert it into DC and output it, the output current and voltage must be adjustable. I know there are AC adapters ...
298 views

### Converting a square wave into a sine wave

I have been researching methods for converting a square wave into a sine wave, but I cannot seem to reach a conclusion. Is it possible to preserve the amplitude and frequency of a square wave when ...
58 views

### Why one pin of AC voltage is grounded in industrial application?

I have an industrial IO module that is an extension of PLC. The datasheet says that if connected AC voltage, you must make one pin is grounded. Why need it be grounded? Why don't they use a bridge ...
1k views

### Measured Q factor of LC circuit does not correspond with calculated and simulated

Still having a problem with measured value of Q factor of parallel LC circuit. My measurememt setup looks like on the picture below. I use Function generator SFG-1003 and Oscilloscope Rohde-Schwarz ...
58 views

### Is this the correct AC analysis of the following circuit?

If I have the following circuit simulate this circuit – Schematic created using CircuitLab Is this AC analysis correct? I am not sure if I should add the R4 resistor in series with the re ...
75 views

### AC Decade Sweep LTSPICE Error

The output plot for Vo/(Vg) is not outputting a smooth curve. I chose a decade sweep with starting frequency 1 Hz and end frequency of 10 GHz. Why is the plot not smooth? I am pretty sure I built the ...
743 views

### I have a AC motor with 3 wires. Black, red and white. How can i connect the capacitor and to power supply as shown on the diagram?

Please help me to understand the diagram attached. I have a motor with three wires. Black, Red, White. and a Capacitor with 2 wires(both Black). 1. How to connect the capacitor to the motor 2. How ...
167 views

### Why not using high frequency AC at homes?

I am a student at school but I learn electronics in parallel as I love it, all my knowledge came from the internet, so if there is a problem in my question please fix it.I came across something called ...
197 views

### Iron losses is equal to copper losses [closed]

Practically how we see Copper losses are equal to iron losses in a transformer
134 views

### Can I use these wires for AC current? [closed]

I bought these wires on amazon, and I noticed in the description that they are rated for 80 volts, and are specifically not to be used for household 110v/220v wiring. However, this wire is basically ...
860 views

### Current calculations

Emergency lighting solution Continuing from the previous post above. Firstly I know how to calculate current in a DC situation. However, since I am using an inverter that produces 220V at its output ...
60 views

### Can multiple LC circuits be connected to the same antenna to listen to different frequencies all at once?

I am very new to this. I am trying to make a radio that listens to multiple stations at once and signal processing circuit that separates frequencies from a microphone signal.
204 views

### When to use X1 or X2 capacitor?

I've a simple circuit where I need to detect AC voltage presence via a microcontroller (ESP32). The ESP32 is a 3.3V device, and requires (worst case) 2.8V to consider a logical one on a GPIO. I'm ...
341 views

### What do apparent power, real power, instantaneous power and reactive power all mean in AC circuits? [duplicate]

We've just started AC circuit analysis in class, and the terms that I mentioned above popped up all at once. I'm new to the idea of phasors(I usually visualize them as arrows making a certain angle ...
81 views

### How to wire a single wire alternator to a bridge rectifier?

I'm trying to make a 25cc weed eater generator (for fun) and I'm thinking of using an alternator to take the rotary output from the engine and turn it into electricity. I need a way to take the 12-14V ...
76 views

### Magnetic field saturation in ac circuit

We have an AC voltage source connected to an ideal inductor that has no resistance.The inductor is wound around a ferromagnetic material. The maximum value of the driving voltage source is big enough ...
81 views

### How can I find i1 and i2 in function of Vg in this circuit?

Given the attached schema I'd love to find the analytical temporal and frequency expressions for the current in the 2 branches: i1 and i2. R0, R1, R2, C1, C2 and Vg(t) are given. In the time domain ...
51 views

### Class A amplifier

So i have to make a circuit for my university, and it has to be made in electronics workbench. I tried to make a class A amp after this schematic: And made this in EWB: My problem is that my circuit ...
39 views

### Delta wye transformer, voltages explanation?

So I'm doing a delta wye transformer simulation in simulink, and I need some clarification about transformer voltages. Here's a image from a youtube video We have phase voltages on primary that ...
58 views

### Power drill motor with no electronics? [duplicate]

I have a Bosch power drill, the same as in this other question. I checked it carefully and it doesn't seem to have a capacitor or any other electronic components. Does it mean the universal motor ...
67 views

### Finding the magnitude of the Transfer Function

This is the circuit, where some of the components values where given and the others, I found myself. (Sorry I have no link to the design, I needed membership there) The following part says to draw ...
335 views

### Isolated mains (AC) presence detector

I need to detect a AC mains outage, isolated way. Output marked as [?] goes to AVR MCU. I don't need to detect undervoltage or zero-crossings. I actually need a simple feedback to MCU interrupt which ...
2k views

### Half wave vs full wave rectifier [duplicate]

I know that a rectifier converts AC voltage into pulsating DC voltage. However, when would you use a half wave rectifier as opposed to a full wave rectifier ? Can you give an example of some ...
496 views

### How to show that voltages on diagram are 120° apart?

So i'm doing a matlab simulation of delta wye transformer and would need to show the phase shift between voltages. Here is a picture of input voltages so how would I show on this graph mathematically ...
74 views

### AC line isolation on multi-level PCB design

Due to space limit I had to design the PCB in multi-level form, the top front side of the PCB is AC line and under that is DC capacitors: Is the 3mm air gap between AC line and DC capacitors enough ...
111 views

### Importance of the apparent power

It is said that, though only active power can actually do work, we have to consider apparent power to dimension the source. But what would seem important to me for that would be to know the maximum ...
69 views

### Draw the corresponding AC circuit

I have the following transistor, whose I have calculated the parameters that were not given. Now, I want to draw the corresponding AC circuit. Can someone help me with this or give me any source ...
132 views

### Help regarding Ac current limiting using resistor

I've 12v(Vrms) 1A AC transformer. I need to regulate it to 1to 4ma maximum output without having much voltage drop. Output load is an animal skin which has resistance in it. Can I just use a ...
39 views

### Pulsing one-way current

In EveryCircuit, they have three different voltage sources, one is DC (left), one is AC (middle), and then one is just pulsing (right) -- Is there a formal name for the 'pulsing one-way-current'? Is ...
93 views

### Can transformers be used to adjust capacitors?

It seems capacitors are subject to a "quality triangle", where we can only pick two out of three desirable traits: High voltage rating High capacitance Cheap For example, a high-voltage high-...
136 views

### How to safely interface 220VAC in a PCB

I am making a PCB circuit that detects the state of a mains voltage switch. Now since I am dealing with mains voltage a lot can go wrong and a lot can go wrong badly so I would like to ask for some ...
100 views

### Amplify AC signal only

I amplify a signal which including AC and DC.Why is the output waveform changed when C1 is 0.1u?And how to decide the value of C1?
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### How to bias an AC signal correctly?

I have an AC signal and want to give it a new DC offset. There are some questions about my experiment results. (The original signal bias and terminal output bias are the same because I want to know ...
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### Finding 70% Voltage Point

Let $v_1$ be the input AC voltage and $v_2$ be the output AC voltage such that gain $\dfrac{v_2}{v_1} = \dfrac{A+jB}{D+jE}$ where $j = \sqrt{-1}$. How should I find the 70% point (the point ...
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### In search for more Exercises

I'm currently studying in Germany for Electrical Engineering (course in English). Due to incoming exam, I am looking for more exercise material as although my course is in English, the school library ...
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### How is the ac load line for the following amplifier derived?

So I am trying to derive the ac load line for the following class A power amplifier First I considered the reflected load/equivalent resistance of the transformer, this becomes R'_{L} = (\frac{n_{...
50 views

### AC Motor voltage

I have a 3 phased AC electrical motor, without any plate on it, so I don't know which voltage should be provided to the motor either 220 or 440V. Is there any way that I can find out?
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### hall current sensor potential failure mode

I was curious what are potential common failure modes for hall-based ac current sensors in a mains ac environment? Specifically those like the acs712 and acs723. Assume you have a 5amp current sensor, ...
281 views

### How does a RC Lowpass filter work?

So I've been trying to understand how an RC lowpass filter works, and I think I got it, but I just need some clarification. My understanding: So an RC Lowpass filter in a nutshell is just a voltage ...
172 views

### Calculation for the distance between maximum swings in the drift distance of electrons

I am currently studying the textbook Practical Electronics for Inventors, Fourth Edition, by Scherz and Monk. In section 2.4.1 Applying a Voltage, the authors have written the following: In the case ...