All Questions
18 questions
0
votes
3
answers
69
views
Why does the resonance peak dampen when an air cored coil is kept on a conducting material?
I was performing an experiment on an air cored coil, when I noticed that the resonance peak of the coil (Real(Z)) in air was sharp, but when kept on an SS316 plate, the peak dampened. When the coil ...
- 95
1
vote
2
answers
173
views
How can this Clapp JFET oscillate when its gate is tied to ground at the resonance frequency?
How does the circuit below oscillate? It seems to have |gain| < 1 at its oscillation frequency of 2.25 MHz, yet it oscillates there.
My analysis:
The DC path is through L4 only, allowing a bias ...
- 1,347
1
vote
1
answer
88
views
External circuit to increase the series capacitance of a resonant circuit
I am working with a long-range reader and antenna coil for a low frequency (135 kHz) RFID application (please see the basic representation below.) The reader features some unknown source impedance, as ...
- 21
0
votes
2
answers
751
views
How to find lossy parallel LC tank Q factor, bandwidth, and half-power-frequency?
Ideal parallel LC tank has infinite impedance at resonance frequency. However, real components, especially inductors, have unignorable ESR, causing ideally infinite impedance dropping to a finite ...
- 623
1
vote
1
answer
423
views
What is the resonant frequency?
I know the formula of resonance frequency for both series and parallel circuits. But when we have a circuit that is shown in the image below where the RESISTOR and INDUCTOR are in parallel and their ...
- 153
2
votes
3
answers
166
views
If the impedance of two coils is measured to be identical at 250.0 kHz, is it safe to assume identical impedance across the spectrum?
This question pertains to matching two air-gap inductors for use in resonant coupling. Alternative solutions are welcomed and appreciated.
The two coils shall be comprised of identical wire.
The two ...
- 353
0
votes
1
answer
852
views
Multiple resonances in a circuit
So I have been struggling a little to understand why when we measure the impedance of the inductance over a large frequency range multiple resonances occur. To do so, I model a 2 turns inductor in ...
- 459
1
vote
1
answer
570
views
How to solve a parallel RLC circuit when the resistor and the inductor are in series
I have a parallel RLC circuit where the inductor is in series with the resistor. The value for the frequency is 200hz and the value for the current of the circuit is 5mA. The experimental answer is 1....
1
vote
1
answer
213
views
Does the self inductance and velocity factor of the elements of a dipole antenna change its resonant frequency?
Below are well known equations from Wikipedia for the resistance and reactance in the impedance of a dipole antenna.
where a is the radius of the conductors, k is the wave number 2πf/c, η0 denotes ...
- 170
1
vote
3
answers
542
views
How do I see the resonance of a high-impedance coil with a VNA?
When it comes to measurements with VNA, my experience tells me that whenever there is a "dip" in the S11 parameter, your takeaway should be that there is a resonance there (this is how the ...
- 139
2
votes
3
answers
757
views
Wien Bridge Oscillator: Why does equating the real part to 0 give the gain equation?
I am learning about Wien bridge oscillators. Following Experiment No. 9: WIEN BRIDGE OSCILLATOR USING OPAMP, they use the following schematic:
They then arrive at the following equation half-way down ...
- 451
3
votes
4
answers
2k
views
Definition of RLC resonance frequency
I have found that a commonly mentioned definition for the resonance frequency in an RLC circuit is defined as the condition where the capacitive and inductive reactances cancel each other, resulting ...
- 189
1
vote
1
answer
506
views
Resonant frequency of RLC circuit
Analysis
I'm trying to find the resonant frequency for this circuit
simulate this circuit – Schematic created using CircuitLab
Writing up the node voltage equation for \$V_o \$
$$\frac{V_o-V_{...
- 4,569
0
votes
1
answer
1k
views
Impedance in LTspice and current plotting
I wanted to try a test simulation on LTSpice to understand few things. I have a RLC parallel circuit and I wanted to see how the impedance varies according to each one of the components (very easy but ...
- 459
1
vote
1
answer
168
views
The equivalent inductance of a RLC in parallel
When studying a system that has the same behavior of an RLC parallel circuit, the slope of the impedance before the resonance corresponds to the value of the equivalent inductance, the slope after the ...
- 459
1
vote
0
answers
496
views
Impedance and resonance frequency of a bias tee
I am a beginner trying to learn about combining impedances and solving for the resonance frequency. I am solving a circuit:
simulate this circuit – Schematic created using CircuitLab
and I ...
- 11
0
votes
2
answers
2k
views
Minimum current at parallel resonance
Does parallel resonance in an AC circuit always result in maximum impedance thus minimum current? If not ,why? I've read this only happens when the parallel branch 'conductances are constant' but have ...
3
votes
5
answers
5k
views
Resonance frequency of an RLC circuit
simulate this circuit – Schematic created using CircuitLab
Is it safe to consider the resonance frequency of a second order RLC circuit to be alway equal to 1/sqrt(LC) or the transfer ...
- 684