28 votes
Accepted

Why are crystal oscillators used in clocks instead of RLC circuits?

Crystal oscillators are much more accurate, they are small, have low temperature coefficients and low drift at a low cost.
user1582568's user avatar
  • 1,895
25 votes
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Ceramic resonator changes and maintains frequency when touched

As said in the other answers, ceramic resonator oscillator circuits are extremely sensitive as they have high input impedance and huge gain. The bias resistance in the circuit is about 1 megaohm and ...
Justme's user avatar
  • 144k
17 votes

Why are crystal oscillators used in clocks instead of RLC circuits?

A quartz crystal is a mechanical resonator with particularly stable properties. Quartz is a very stable material -- it doesn't 'age', or change much with temperature. It is also possible to prepare ...
jp314's user avatar
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13 votes

Why do these two sets of seemingly identical capacitors behave differently?

Classic type 2 dielectric behavior. All capacitors of this class have a voltage dependency (ferroelectric saturation), meaning C decreases as |V| rises. Evidently you have a particularly sensitive ...
Tim Williams's user avatar
11 votes

Could a copper RF cavity like this be reasonably expected to have a Q > 7000?

Yes, a quality factor of 7000 is not even near the upper limit for cavity resonators made of copper at that frequency. Microwave copper cavities with quality factors of \$10^6\$ are not uncommon. ...
metacollin's user avatar
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11 votes
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Why do these two sets of seemingly identical capacitors behave differently?

Y5V is a nasty Class II dielectric- the worst much in present-day use, I think. I wouldn't even use it for a bypass capacitor let alone resonate something with it (it might be acceptable for a toy ...
Spehro Pefhany's user avatar
9 votes

Measure temperature on a moving engine valve: transfer voltage and reading wireless?

A good way might be to use a pyrometer. It is an optical device that receives the heat/light emitted by the object whose temperature needs to be measured and then uses part of that "spectra" to ...
Andy aka's user avatar
  • 453k
9 votes
Accepted

Does a voice coil vibrate at the same frequency as the source sound file?

I would expect so, assuming the speaker is capable of vibrating with the same speed. As far as I know each speaker has a range in which it can vibrate (usefully). Mostly bigger speakers are better ...
Michel Keijzers's user avatar
9 votes

Does a voice coil vibrate at the same frequency as the source sound file?

An ideal speaker will vibrate at whatever frequency of signal you drive it with. However, in reality, there are a few constrainsts. The amplifier output you are driving it with has a frequency range ...
Trevor_G's user avatar
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9 votes
Accepted

Skim excess power from a resonant circuit without draining it?

One definition of Q is energy_stored/energy_lost_per_cycle. Increase the losses, to your pickoff, and you necessarily decrease the Q. If you have a parallel LC at some point in your oscillator, then a ...
Neil_UK's user avatar
  • 165k
8 votes

Intuition for resonant, natural, and oscillatory frequencies of RLC circuits?

There are quite a few subtle differences between band-pass and low/high filters but, for a simple LCR band-pass filter, damped and un-damped resonant frequencies are the same numerically and ...
Andy aka's user avatar
  • 453k
8 votes
Accepted

Why do real LC oscillating circuits not oscillate at the resonance frequency?

According to the oscillation condition (Barkhausen) a circuit with frequency-dependent feedback can oscillate only at a frequency where the loop gain is unity (or slightly larger). In particular, this ...
LvW's user avatar
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7 votes

Resonance frequency of an RLC circuit

It is important to realize that the resonance frequency (i.e., the frequency at which the circuit resonates if the damping is sufficiently low) of a second-order RLC circuit never equals \$\frac{1}{\...
Matt L.'s user avatar
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7 votes
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Resonance frequency of an RLC circuit

KCL: (\$v_o\$ over your output, \$v_i\$ over voltage source and \$v\$ over the internal node: $$ \frac{v_o}{R_3} + \frac{v_o-v}{Z_{C1}}+\frac{v_o-v_i}{R_2} = 0 \\ \frac{v}{Z_L} + \frac{v-v_i}{Z_{C2}} ...
Pål-Kristian Engstad's user avatar
7 votes
Accepted

Inductor's self-resonant frequency: Do we want it to be high or low?

In this case, is it smart to use an inductor with SR frequency below 1 MHz or over 4 MHz? Above the self resonant frequency the impedance of the "inductor" is capacitive i.e. it stops being like an ...
Andy aka's user avatar
  • 453k
7 votes
Accepted

How to calculate Resonance Frequency of Audio Speaker?

You cannot CALCULATE Fs, (Resonant frequency of loudspeaker moving mass in free air). But you can MEASURE it relatively easily. You will need a power amp, a variable frequency source, and a DMM. ...
Richard Crowley's user avatar
7 votes

Resonant Solenoid Drivers

In no case would a coil driven at resonance be better than one driven with DC. This is presuming that the job of the coil is to make a magnetic field, and that this requirement exists regardless of ...
Olin Lathrop's user avatar
7 votes
Accepted

why do resonant inductive coupling circuit operate at high frequencies?

Low frequency resonant tuned circuits require high values of inductance and capacitance. High value and power efficient inductors cost money and are big thus, they don't easily find much use in ...
Andy aka's user avatar
  • 453k
7 votes

Ceramic resonator changes and maintains frequency when touched

Ceramic resonators have overtone modes, like quartz crystals. Here's a picture, taken from this page by ECS. You can see the main mode, at about 455kHz, and a couple of other modes a bit above 1MHz. ...
TimWescott's user avatar
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7 votes
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Definition of RLC resonance frequency

For example, the RL-C series-parallel circuit I'm assuming here you mean a series connection of a resistor and inductor where that series pair is in parallel with a capacitor. The impedance of that ...
Andy aka's user avatar
  • 453k
7 votes
Accepted

LT Spice: parallel RLC circuit resonator giving weird frequency response?

This is a likely candidate for show-stopper of the month: - Then, when you fix that you'll realize that a voltage source (V1) is ideal and won't care a damn about C1 and L1 being present i.e. you'll ...
Andy aka's user avatar
  • 453k
7 votes
Accepted

Do you know about topologies that look like this?

This is a 3-level single-phase boost converter. I think it has been originally presented in a paper at APEC in 1995: You can simulate this structure with SIMPLIS for instance and the below circuit is ...
Verbal Kint's user avatar
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6 votes
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How to overcome transistor heat in slayer exciter?

Have you tried finding the current through the coil? Find the current through the coil. You can either simulate it with a spice package or place a meter between the coil and transistor. Once you know ...
Voltage Spike's user avatar
  • 81.3k
6 votes

Measure temperature on a moving engine valve: transfer voltage and reading wireless?

I think this could be done with a ribbon or thin wire thermocouple attached to the top of the valve. I would suggest looking at making a blind hole (say via EDM plunge) in the valve and put a ...
Spehro Pefhany's user avatar
6 votes

Measure temperature on a moving engine valve: transfer voltage and reading wireless?

This is tricky, so the first thing you need to do is get someone that knows what they are doing with electronics. The high temperatures and vibration make this difficult, regardless of how you ...
Olin Lathrop's user avatar
6 votes

Antiresonance of multiple parallel decoupling capacitors: use same value or multiple values?

You're doing pretty good on getting to the parallel resonance already. It depends on your application. If you're trying to suppress/bypass for example ethernet peaks, you should use parallel caps ...
Barleyman's user avatar
  • 3,616
6 votes

Antiresonance of multiple parallel decoupling capacitors: use same value or multiple values?

I have a bunch of observations that I decided to make into an answer and please note that I'm quite happy to spend 30 minutes doing a simulation of this if someone can precisely state what the test ...
Andy aka's user avatar
  • 453k
6 votes
Accepted

Confusing quartz crystal impedance graphs

Look at this graph: - The vertical axis is purely impedance and the parallel impedance coincides with the peak impedance. Adding more parallel capacitance lowers that high-impedance point. Look at ...
Andy aka's user avatar
  • 453k
6 votes
Accepted

Why is the ouput so low in this LC resonant circuit?

EDIT: I was hoping to see voltage amplification when the circuit was at resonance without using any active components, not even batteries, using only the input signal. Now I see that this is not ...
Andy aka's user avatar
  • 453k
6 votes

What are the resonant frequencies for this RLC circuit?

The fun is in determining the transfer function (TF) symbolically otherwise you don't know what elements contribute to the resonant frequencies. You can use the brute-force analysis to determine this ...
Verbal Kint's user avatar
  • 21.9k

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