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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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How far can an AC signal actually go?

I have the following circuit schematic: simulate this circuit – Schematic created using CircuitLab The systems is a water level control circuit, in which a signal is sent from the water level ...
Je parle avec toi's user avatar
3 votes
3 answers
319 views

How can the diode conduct in negative half cycle of AC signal in clamper circuit?

Could you kindly help me understand the clamper circuit. I watched a couple videos and I'm confused. My confusion is in positive clamper circuit. How can the diode conduct during the negative half ...
Marjan Ovcar's user avatar
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0 answers
23 views

Protection circuit for inverter or generator during blackouts

During blackouts in Ukraine it's a common practice to turn incoming AC voltage switch off and power all in-house power AC lines with an inverter or a gas/diesel generator. Can someone share a ...
Kostyantyn Sushchyk's user avatar
-3 votes
2 answers
72 views

What is the correct formula for the 3 dB frequency of an RC or LC Circuit?

Before we jump to another post where the formula is I am reading through the text book Microelectronic Circuits 8th edition by SEDRA/SMITH. In the text, they show this table. Here it shows the time ...
Noahwar97's user avatar
0 votes
1 answer
40 views

3-Phase system Voltage conversion

If we are converting from Y to delta configuration or vice-versa, how do we convert the phases of our voltages? I've seen that we need to add or subtract 30 degrees from one another, but I don't ...
Electricity's user avatar
0 votes
2 answers
88 views

What is the role for each of these AC coupling components?

I'd like to learn more about the RP2040 PWM Audio AC coupling circuit found in figure 22 in this document. Figure 22. Schematic section showing the Analogue PWM audio circuit Even though I understand ...
Erik's user avatar
  • 101
0 votes
1 answer
59 views

Non contact AC voltage detector circuit current calculation

This seems to be a common circuit for a non-contact AC voltage detector: Non-Contact AC Line Detector using BC547 The probe generates a small amount of current when it is near an AC line due to ...
Kailash Kumaravel's user avatar
1 vote
3 answers
178 views

How is the reactance of a capacitor formulated?

Question: Understanding the Reactance of a Capacitor Hi everyone, I'm having trouble formulating the reactance in a capacitor and would appreciate some help. Here's what I understand so far: We have ...
DPV's user avatar
  • 13
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0 answers
62 views

Contactless AC line detection using a single transistor

I have seen circuits that are used to detect the presence of AC voltage without any contact, like the one below. Non-Contact AC Line Detector using BC547 I have tested this circuit and it works fine. ...
Kailash Kumaravel's user avatar
2 votes
1 answer
67 views

I'm trying to wire this motor I have, but I'm not sure how to read this diagram

This motor is 110V or 220V. I'm trying to wire it up for 110 but I'm not 100% sure how. Is low std 110V and high 220V? I believe I need to connect 1,3,8 to hot and 2,4,5 to neutral and ground to the ...
Nick's user avatar
  • 21
1 vote
2 answers
51 views

Potentiometer for Kitchen Fan

I'm exploring the possibility of building a potentiometer for my rangehood fan. The manufacturer (FanTech) of the fan actually sells one (EC-10VHL) but I'm having a hard time trying to find a ...
vince chung's user avatar
1 vote
0 answers
49 views

Identification of 3 pin connector for the power supply of the TI silent Model 703/707 Data Terminal [closed]

I want to restore a TI Silent 700 model 703/707 that lacks the power supply. The power supply provides 20 VAC 35 VA with 3 pins ...
Jonas Stein's user avatar
0 votes
1 answer
51 views

AC Stepdown transformer blown troubleshoot

I've had a ring doorbell pro for about 5 years, it's wired directly to the following transformer output 1 & 4 (24v): It's using the original doorbell wiring, which rightly or wrongly, was wired ...
JamesWilliams's user avatar
1 vote
1 answer
223 views

Food for thought: Which person has truth in this discussion on capacity and AC? [closed]

I have stumbled upon interesting discussion in the commentary section regarding safety of electrical engineering in home environment. person1: AC voltage 'flows' even through insulator, fact. person2:...
Tony_12652985's user avatar
1 vote
1 answer
93 views

How to find the power factor of a component when the combined power factor and one other power factor is known? [closed]

Problem: A 2000 volt-ampere with a power factor of 0.8 lagging is combined with 500 volt-amperes of synchronous motors. If the overall power factor is 0.9 lagging, find the power factor of the ...
tryingtobeastoic's user avatar
0 votes
3 answers
97 views

DC bias vs AC voltage change rate on MLCC capacitors

I'm looking at this 10uF X5R ceramic MLCC capacitor. I know that ceramic capacitors which aren't C0G have an significant variation of their value depending on voltage, temperature, aging, and ...
Filippo's user avatar
0 votes
0 answers
22 views

A scheme to control a number of ceiling light bulbs being on with a single switch [migrated]

I have a ceiling light with two bulbs and only two wires (live and neithral) arriving to it (220-250v AC) and a SPST switch. I want to connect one bulb directly to those wires and I want the other ...
Hug you Nvidia's user avatar
2 votes
1 answer
227 views

I'm getting 60-130V of output from a 5V voltage regulator. Does anyone know what went wrong?

I made a 5V power supply, but when I connected my multimeter probes to the output lines of the supply it read 60-130V. the voltage after the rectifier should be around 18-19V. If anyone can give a ...
catandmoose's user avatar
0 votes
0 answers
39 views

How to measure power supplied by H-bridge inverter?

System description: H-bridge network of IGBTs (inverter) is used to supply power to a parallel LC circuit connected through matching inductor. It is desired to measure and regulate the power supplied ...
AR2020's user avatar
  • 76
0 votes
0 answers
42 views

Wiring Portable AC to Run at Max

I'd like to wire this portable AC to always run at max (compressor on and fan at max speed). I'm using it for a project where the temperature is going to be controlled by controlling the power to to ...
KingLouis_CLXXII's user avatar
3 votes
3 answers
853 views

Transformer with same size symbol meaning

I Know these symbols mean a transformer step up or down: But what does this one represent since it has the same size on both sides? Part above taken from this schematic: And this also has me ...
StealthRT's user avatar
  • 797
0 votes
2 answers
54 views

Are \$v_{C}\$ and \$v_{L}\$ in phase in an LC oscillator?

Looking at these figures, I can't help but to conclude that \$v_{C}\$ and \$v_{L}\$ are in phase! Why? Well, because \$v_{C}=q/c\$ I know this is wrong but why? Reference: https://shorturl.at/30NEu
Jack's user avatar
  • 361
1 vote
0 answers
58 views

Is there a DC voltage on a transmitter power amplifier's output?

When studying the answers to Are my power calculations on this MOSFET Power Amplifier accurate? , I noticed this contradiction: If you integrate V * A, you get ...
SRobertJames's user avatar
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0 votes
1 answer
66 views

18 V AC to 5 V DC circuit design with battery

I’ll start by saying I have little understanding of electronic circuits. I have an old door phone to which I have connected a wireless switch in order to be able to open my door with a remote control. ...
ManosK's user avatar
  • 1
0 votes
1 answer
52 views

Power Supply is arced and fuses opened

Note: PFC circuit is bypassed I have my own designed circuit and this circuit is get input of 220VAC/50Hz. Inside of circuit bridge rectifier and filters are exist with this circuit we get 320VDC. So ...
MSB's user avatar
  • 27
-1 votes
1 answer
84 views

How does an AC of 5100W (1.5 ton) capacity work without any issue with 1000W of total electricity load of my house? [closed]

I have one AC of 5100W (1.5 ton) capacity and I generally run it along with other appliances like fans, LED bulbs, TV and more. My house is sanctioned ...
NSPratik's user avatar
  • 139
12 votes
6 answers
3k views

Second opinion on PCB design for relay made in Altium

Edit: I have added the updated PCB design at the bottom over this post (for anyone curious about the progress) And a big thanks to everyone who commented, it really helped me out a lot! Original ...
Djumbonia's user avatar
  • 137
0 votes
2 answers
85 views

Understanding Current Ratings in Step-Up Transformers

A step up transformer increases voltage while decreasing current because we can't get more energy than what we had in the first place. The thing struggles my mind is how his power has a current rating?...
kaan's user avatar
  • 377
1 vote
1 answer
61 views

Can someone help me with a LED light fixture puzzlement? [closed]

I have been buying and using LED bulbs from the Dollar Tree for many years. I have never had an issue with them in the past. Just the occasional burn out in my home office fixture because it stays on ...
russT's user avatar
  • 41
0 votes
1 answer
60 views

Power consumption in AC circuit

In a purely resistive circuit, maximum power is consumed. Why? Because, we say, current and voltage are in phase. While in a purely inductive circuit, power consumed in a cycle is zero. Because, ...
KeShAw's user avatar
  • 1
0 votes
4 answers
54 views

About power factor in circuits

We have an AC circuit with rms voltage V, and resistor R. Assuming that the circuit does noy contain any reactive components, Z=R therefore the rms current flowing in the circuit can be obtained by I =...
SleepingOwl132's user avatar
0 votes
2 answers
37 views

Dealing with High Voltage Low Current Transformer Inrush and bypassing a Thermistor

As a learning project, I am designing a power supply section of a guitar amplifier that uses a 120V Primary, 250V 45mA 40VA Secondary Transformer. Without any thermistor in-line on the main supply, I'...
Tyler B's user avatar
  • 53
1 vote
0 answers
68 views

How does the "earthing" system works in a UPS

PLEASE SEE EDIT 1 I want to know how exactly the earthing system works in a UPS, an example with by the ECOFlow RIVER 2. From their webpage it seems so simple, you charge the battery, switch the AC, ...
JoeyB's user avatar
  • 2,391
4 votes
2 answers
333 views

Should this bare minimum TRIAC circuit light the bulb? [duplicate]

In trying to build a multi-channel, optoisolated, TRIAC based, switch module, I could not even get one channel to function properly. Trying to isolate the problem, I've reduced the circuit to this ...
gdee's user avatar
  • 75
0 votes
0 answers
58 views

How to reduce notches in input AC voltage for Totempole Power factor Correction circuit?

Respected readers, I am working with a totem pole PFC circuit. In an experimental study, I face a problem of high-frequency notches in source voltage (Yellow one). I found an explanation behind this. ...
Saprativ Saha's user avatar
1 vote
0 answers
35 views

Capacitance for power factor correction formula

I wrote a test the other day and the paper provided a formula for calculating the required capacitance needed for power factor correction. The formula: \begin{align} C = \frac{Q_c}{\omega V_{RMS}^2} \...
Gideon's user avatar
  • 35
2 votes
2 answers
178 views

Power transformer design calculations

I´m currently designing power transformers in a pretty basic way, using AWG tables for the section of the copper wire, and not knowing what are the real losses, just overdesigning. Three phase ...
samuel mattio's user avatar
0 votes
1 answer
43 views

Is steady state ac circuit analysis possible on a purely inductive circuit?

Is steady state ac circuit analysis possible on a purely inductive circuit? Consider the circuit: The dynamics should be: $$ v_1 = L i^\prime + Ri + v_2\\ i(0) = i_0 $$ Now, say we do steady state ...
wyer33's user avatar
  • 105
0 votes
1 answer
74 views

How to measure the voltage drop of the power supply when a large load (20 amps) is briefly connected for 20 milliseconds (one cycle of the waveform)

I want to measure the peak voltage of 240V AC supply line accurate to (±5%) within one cycle of the supply waveform, i.e. 20 milliseconds. What should be min. sampling rate and the ADC resolution (12 /...
Jitendra Mahapatra's user avatar
0 votes
1 answer
55 views

LTspice AC/DC converter with DC/DC boost converter

So this is my first time using LTspice and I need to convert my (AC) Vin 11.5V to DC and then boost DC voltage to Vout 22.5V. I have a few givens and some I needed to calculate. I am struggling to ...
Richard Lewis's user avatar
0 votes
1 answer
86 views

Can I use the mains itself as a ground? [closed]

Basically, an ideal EMC/EMI filter looks like the below circuit diagram. Ideal EMI filter circuit: Can I use the mains itself as a ground instead of using a physical ground? My take on EMI filter ...
Mrinmoy Sarkar's user avatar
5 votes
3 answers
826 views

Telecom cables for power transmission

Summary: Can I use abandoned telecom wire bundles as a 3-phase neutral? Our campus currently has underground AC cables supplying 2 legs of 3 phase wye power to a remote (50 ft away) building. There ...
madarp's user avatar
  • 63
0 votes
3 answers
63 views

Can this circuit be used for an AC-DC emergency LED lamp?

Basically, this circuit is supposed to light the LED lamp from either AC or the battery. When there is AC available the bulb will glow with the power of AC and the battery will be simultaneously ...
Mrinmoy Sarkar's user avatar
0 votes
1 answer
48 views

MDAC AC reference input

I previously had a question on using AC reference voltage with a MDAC, But it has been addressed nicely in the answer below. How does the "Multiplying Bandwidth" specification relate to a ...
Chetan Karkera's user avatar
0 votes
2 answers
115 views

Are the answers of this questions all incorrect? [closed]

The question is: What is the voltage of the AC voltage source if Ammeter 1 measure 0.6A and Ammeter 2 measures 0.8A? R1 is 10 Ohms R2 is 20 Ohms (See image below) My solution is : voltage at R1: (0....
LEXOR AI's user avatar
  • 346
0 votes
2 answers
51 views

How to wire a repurposed ac motor

I have an old garage door opener that I would like to repurpose. I would like to bypass the normal garage door logic and add an on-off-on switch. When switched to on1 rotates in direction 1, when ...
Jacob L's user avatar
0 votes
2 answers
50 views

Deriving AC max. average power transfer, where am I wrong?

Starting with the Thevenin equivalent voltage \$V_{th}\$, impedece \$Z_{th}\$ and load impedence \$Z_l\$, the maximum average power transfer seems to be given by \$\frac{|V_{th}|^2}{8R_{th}}\$ but I'm ...
MrFregg's user avatar
  • 105
0 votes
1 answer
64 views

Does LC circuit convert DC to AC?

I was experimenting with LC circuit (Class 12 - Physics, India) in CircuitJS1 Simmulator. Interestingly, the LC circuit given below was converting DC into AC. Circuit: Circuit Specifications: DC ...
Mrinmoy Sarkar's user avatar
8 votes
1 answer
1k views

How can I make this AC current switch turn on at 20mA instead of 50mA?

I've bought this AC current switch, which is sensitive to currents from 50 mA to 5 A on the single AC wire that passes inside its hole. When currents from 50 mA start to flow in the wire, it allows ...
Rodrigo's user avatar
  • 567
0 votes
0 answers
49 views

Wiring AC 5 Wire Motor with 4 Phases to Run at Max

I'm trying to hardwire a fan motor to always run on max. Currently, it has a circuit board that allows you to adjust the speeds and requires a bit of fiddling to turn on and set the speed when the fan ...
KingLouis_CLXXII's user avatar

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