New answers tagged ac
2
votes
What is the correct formula for the 3 dB frequency of an RC or LC Circuit?
Facts:
There are \$2\pi\$ radians in one complete revolution of a circle.
It's the circumference of a circle with radius 1.
If that circle revolves at 1 turn per second (equivalent to a frequency of ...
- 465k
2
votes
What is the correct formula for the 3 dB frequency of an RC or LC Circuit?
Angular frequency Omega is 2pi*f so the formulas are correct.
- 159k
1
vote
3-Phase system Voltage conversion
Made with microcap v12.
You can construct the "voltages" using a simulator.
Just see this. Just a difference of "30°".
R, S, T in that order ... R-S, S-T, T-R ...
- 14.5k
2
votes
Non contact AC voltage detector circuit current calculation
Realize that this circuit was most likely created by a hacker, not an Engineer. Its characteristics are highly dependent on the beta of the transistors. An ESD discharge to the input will most likely ...
- 16.5k
2
votes
What is the role for each of these AC coupling components?
Multiple components do multiple things.
And this isn't simply just AC coupling any more. It's much more than that.
R1 220 ohms rises the digital buffer IC output impedance, i.e. it limits the current ...
- 159k
2
votes
What is the role for each of these AC coupling components?
A PWM signal swinging between 0 and a positive peak can be considered as the sum of an AC signal and a DC offset. DC offset is the avg (mean) value which is equal to the duty-cycle of the PWM signal ...
- 36k
4
votes
Accepted
How is the reactance of a capacitor formulated?
The math
Consider this linear differential equation with real coefficients
$$\frac{\text{d}\ y(t)}{\text{d}t} + a_0y(t) = b_0x(t) \tag1$$
Assume now that the input and output are complex valued ...
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2
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How is the reactance of a capacitor formulated?
How exactly does the reactance formula Xc=1ωC come about?
\$\mathbb{V}=V_0\exp\left(j\,\omega t\right)\$. (Note: The vector length is unchanging. It's tip forms a helix traveling in time. A voltage ...
- 11.2k
1
vote
How is the reactance of a capacitor formulated?
In an ideal capacitor, there are no parasitic resistances so the real component to the impedance is just zero and the phase angle is -90 degrees or -j. It can also be written as Z = 0 - jωC.
In real ...
- 20.3k
0
votes
Power IR2110 from a low voltage AC Source
You have connected your "DC Output" of the bridge to the AC input.
The cathodes of D1 and D2 are the positive output of the bridge, and anodes of D3 and D4 are the negative output of the ...
- 59.9k
0
votes
Are there any regulations that disallow simple AC-to-AC mains to low voltage power supplies?
AC adapter? What you are describing is not an AC-to-AC adapter. They are transformers, and the transformer makes it safe by inserting a large impedance between the user and the utility. There is ...
- 652
0
votes
DC bias vs AC voltage change rate on MLCC capacitors
Prerequisites: calculus, derivatives; E&M, static fields; definition of capacitance.
Consider the construction of a capacitor:
We have two parallel plates (or anything equivalent to them: a roll, ...
- 39.7k
0
votes
Accepted
DC bias vs AC voltage change rate on MLCC capacitors
You seem to be interpreting the results without considering the test conditions.
Let's start with DC bias test.
The website says the capacitance vs DC bias is measured with 0.5VRMS AC signal (...
- 159k
2
votes
I'm trying to wire this motor I have, but I'm not sure how to read this diagram
You are correct. This is a split-phase, capacitor-start induction motor. It runs from a single phase AC power source. How it works:
For the higher voltage, the two "A" phase coils are ...
- 11.6k
0
votes
Potentiometer for Kitchen Fan
Cheap speed control modules for fans are typically built around a capacitor that will form an impedance divider, with a purely reactive impedance. So it will reduce the voltage seen by the motor, but ...
- 1
0
votes
Potentiometer for Kitchen Fan
The silver component is in fact a capacitor, the code you read on top of it probably means 4.7uF rated for 35 volts and the 169 is the date code or some series number, the main thing you need to focus ...
- 153
2
votes
Accepted
AC Stepdown transformer blown troubleshoot
What would cause a transformer to fail across the primary, from simply switching a breaker off, then back on?
It cooled down when the breaker went off then, it warmed up when the breaker was ...
- 465k
4
votes
Food for thought: Which person has truth in this discussion on capacity and AC?
person1: AC voltage 'flows' even through insulator, fact.
False, category error. Voltage doesn't flow, current flows. We could say that it's sort of true about insulators, if you are allowed to ...
- 169k
1
vote
Accepted
How to find the power factor of a component when the combined power factor and one other power factor is known?
As you correctly surmised, you can't add the magnitudes of complex power as ChatGPT says because they're vectors, but you can add them as vectors.
Please forgive my drawing skills.
Edit: the ...
- 20.3k
0
votes
DC bias vs AC voltage change rate on MLCC capacitors
From your example case I assume that you are thinking of adding DC and AC bias together, but this is not how it works.
Think of DC bias as a change of charge capacity (like a battery) depending on ...
- 7,653
0
votes
AC capacitor computational problem using calculus
Since current \$i(t)\$ is discontinuous at time \$t=1\mu s\$, the calculation must be piecewise, the sum of integrals over two distinct intervals, but the equation for \$i\$ during each interval is ...
- 39k
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