Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [phase]

For questions about AC phases (e.g. three-phase systems) or phase in the context of waves, transfer functions, etc. Consider using in conjunction with related tags such as "three-phase", "transfer-function", etc., as applicable.

For questions about AC phases (e.g. three-phase systems) or phase in the context of waves, transfer functions, etc. Consider using in conjunction with related tags such as , , etc., as applicable.

See Wikipedia's articles on polyphase systems and phase in the context of waves for more information.

313 questions
52
votes
11 answers

Why three-phase power? Why not a higher number of phases?

Is there a reason, beyond historical reasons, that three phases has become the dominant number of phases? I am aware of the advantages against one phase and two phase, namely the reduced amount of conductor needed, and that motors can provide torque…
Hugoagogo
  • 2,405
  • 3
  • 22
  • 29
33
votes
3 answers

Why 3 phase and not 1 phase power transmission?

Why does power transmission use three lines with three different phases? Why not three lines all in the same phase? Does it have to do with the alternators used for generating the power, or is there less loss when the phases of the three lines are…
Geremia
  • 471
  • 1
  • 5
  • 12
22
votes
7 answers

Staying in Phase On The Grid

I have been an EE for over forty years and never did find out the right answer to this one.... How do power-stations and transformer switching stations ensure that the power they are feeding into the grid is in-phase with the existing power on the…
Trevor_G
  • 46,364
  • 8
  • 68
  • 151
11
votes
6 answers

Comparator: Noisy sine to square wave, how much phase noise?

In a circuit a comparator is used to convert a sinusoidal signal to a square wave. The input signal however is not a clean sine wave, but has some noise added to it. The comparator is supposed to be ideal and has a hysteresis which is much larger…
kassiopeia
  • 432
  • 1
  • 6
  • 15
7
votes
1 answer

How to find phase angle from transfer function

From the function: $$H(\omega) = \frac{1}{(1 + j\omega)(1 + j\omega/10)}$$ How is the phase angle obtained when it has multiple poles to get: $$\phi = -\tan^{-1}(\omega) - \tan^{-1}(\omega/10)$$ What rule of phase angles allows you to separate the…
calvinjarrod
  • 125
  • 1
  • 1
  • 9
7
votes
2 answers

Why do we use a diac for triggering a triac?

I mean, Wouldn't it be possible to give a gate pulse on triac directly? I have seen in many phase control application circuits like fan speed control,the usage of diacs to trigger a triac.
Rahul Manoj
  • 123
  • 1
  • 2
  • 4
6
votes
2 answers

How is the gain/phase vs frequency measured for opamps?

Opamp manufacturers post graphs like these in datasheets: How is the data for this graph measured? Is it calculated using the mathematical model of an opamp?
miceuz
  • 5,523
  • 3
  • 39
  • 49
6
votes
5 answers

Why doesn't the bypass capacitor cause phase shift in this oscillator circuit?

I am trying to understand oscillator basics. I thought I already understood how a capacitor works, but I still get confused about it. This circuit is an RC phase shift oscillator. I understand that we need 3 capacitors to get a 180° phase shift in…
Darko
  • 73
  • 3
6
votes
2 answers

Why do crystals have 0° phase shift at series resonance?

I am trying to understand the inner workings of crystal oscillators, but I do not understand why the current has 0° phase shift at series resonance. To my knowledge this is the equivalent circuit for an crystal oscillator. simulate this circuit –…
Brent Morris
  • 61
  • 3
6
votes
1 answer

Find the phase angle between two functions

Apologies if this is better suited for a mathematics forum, it's from my circuits textbook so I've decided to post here. Below is a practice problem from the textbook, with the provided solution. If I try to convert i1 to a positive cosine…
Aaron
  • 95
  • 5
6
votes
1 answer

What does actually the "unravel branch wrap" option do to the phase plot in LTspice?

Below two Bode plots are identical just that in the second one the option "unravel branch wrap" is unticked for the phase plot: What does this option do to the phase plot?
user16307
  • 11,802
  • 51
  • 173
  • 312
6
votes
2 answers

Manual transformer winding - dots convention

I've already seen this and this. But I can't decide how to correctly wind a SMPS transformer. This is the transformer: I mantain the same turns direction (CCW if you look at transformer from the top). I start winding the first half of primary. I…
Cornelius
  • 5,048
  • 4
  • 26
  • 45
5
votes
4 answers

Transformer 220/380/440 V 24 V explanation

I have a circuit that uses three-phase electric power (without neutral). There is an old transformer in this circuit (see image). It converts 220-440 V to 24 V. The input has the handwritten numbers "0", "220", "240", "380", "415", and "440" on it.…
Dimitris
  • 83
  • 4
5
votes
3 answers

About the torque-free charging operation

I and one of my friends are working on understanding the below context (paper link): The study provides an extensive overview of on-board integrated chargers for electric vehicles that are based on multiphase (more than three phases) machines and…
Soheil Paper
  • 1
  • 1
  • 3
  • 25
5
votes
2 answers

Finding phase shift between the voltage and current

I am trying to find the phase shift \$\phi\$ of this circuit. I am using the formula: $$\phi = \arctan{\left(\frac{X_{L}-X_{C}}{R}\right)}$$ Substituting in the values: $$\phi = \arctan{\frac{2000\Omega-4000\Omega}{6000\Omega}}$$ $$\phi =…
weno
  • 179
  • 8
1
2 3
…
20 21