I studied 3 years of technical school and 5 years of engineering and never saw so better explanation. Don't know why to spend years doing calculations when a practical lesson like this one sace years of time
You've made me do one thing my teacher was not capable to do through the whole semester: make me think over what we were studying. Thank you for that, honestly.
Love your video, perfect explanation, using the scope and the theory! I’ve been studying this for years and have never had such a clear and concise explanation. Thank You!!
Watch many of your videos and they are amongst the very best - thank you. Despite the excellence of your material I find it useful to replicate your demonstrations - there is even more learning to be found! This one for example - at resonance the source is effectively shorted and mine doesn't like that. Also haven't found a way to hide a trace on the scope that is used in math but not needed on the display. Excellent skill building experiments. Brilliant. I encourage anyone to try reproducing what seem at first to be simple circuits.
I've just started looking at tuned circuits as part of prep for a licence exam and found this a very helpful perspective to understand why the basic LC circuits behave as they do.
My "teacher" in Uni made a complete dogs dinner of this despite having all the resources of a modern Uni at his disposal. You totally nailed it with some graph paper, a scope and $0.000000002 in components.
Since a long time i am searching for hardcore electronics hardware vedios, your vedio are amazing keep making vedios on more complex electronics hardware
That's awesome I was struggling to understand why one lagging the other mattered and then you went "above and beyond" the resonant frequencies skewing and squashing the waveform. Outstanding, I have the next step ahead of me!
Excellently explained, finally understood this concept: at resonant frequency the resistance/impedance is zero, effectively acting as a short! Perfect!!!
I agree - pure gold! By far the best and clearest videos on these subjects on youtube. To the above suggestion on filters I wish to suggest adding 'back to basics' videos on the following: 1. Ground - difference between DC/AC circuits, floating ground, ground loops and how to avoid them, best practices and the how and where to use isolation transformers and how they work 2. RC oscillators. 3. Which capacitor/inductor types are good for which applications and which values to use.
Awesome video. Your explanation is loaded with detail but yet very simple to understand. The series LC circuit is exactly what we use on the railroad for our crossing circuits. Each RR crossing has it's own frequency and there is a series LC just as you described at either end of the approach to terminate the circuit and define the limits of the approach. This allows multiple crossing approach circuits to be stacked upon one another, each with it's own frequency and tuned termination shunts (the series LC). It also allows our DC signaling pulses to pass through unimpeded.
Excellent video. As a lapsed electrical engineer it makes me want to watch a few more. I was intrigued by the pencil drawings. I never thought that they would work so well in a video, but they do.
Aww haa! Now I understand the why of the left channel fault on a tape machine I repaired. I knew something was off with the left side bias trap by intuition. After looking at your video, I was able to confirm that the bias trap had drifted off frequency by 12KHz. Really cool stuff you've offered. Thanks. Now, as to why I've chosen tape machine repair as a hobby, I'm afraid there's no help for it. Actually, I try to repair everything :-)
In the parallel circuit, you could put 1 Ohm resistance in series with L and C (on the ground side) to show the phase relation between the currents. Once again, they are always out of phase and resonance is when their amplitudes are equal -- V/X_L = I_L = I_C = V/X_C. Cross multiply and cancel V to see X_L = X_C once again at resonance.
Yes sir! This helped out a lot having your explanation coupled with the oscilloscope and your diagrams. This tied some loose ends in the education. Thank you!
Clarity , instruction and demos are simply fantastic. Thank you so much . Had trouble fully conceptualizing rc and resonances until I saw this. I love it . I would love to understand more about the application. You mentioned at resonance, useful things can be done . Would love know more about this is used in application . Thank you . Subscribed, and liked
Thank you Allen. I thought I've watched all your videos but every once in while a "new" old one pops up. :/ I've been playing with electronics my whole life, Science Fair kits, fixing VCRS, resoldering broken jacks, I even wanted to be go to school for EET) but it wasn't until I started watching your videos that things clicked. I love your back to basics keep them coming :). Btw. Your lucky I'm not your next door neighbor I'd be bugging you everyday.
Thank you. Im just started getting into RF and didn't understand how the local oscillator selected the frequency from the antennae in the tuner circuit. I understood that the local oscillator had a resonant frequency it oscillates at but i didn't see how it discriminated out all the different incoming frequencies from the antennae. Now I think I see that the parallel LC circuit will short the unwanted frequencies to gnd and effectively pass-through the selected frequency along the signal path by virtue of it effectively acting as an open for that frequency. I'm sure I don't fully understand it still but this was helpful. Thanks.
That is part of it (tuning the front-end bandpass filter), but the main thing that involves the local oscillator is the mixing circuit. This video might help: th-cam.com/video/Vf06HSR4LdY/w-d-xo.html
I can not express the importance of this video for those want to learn electronics. once you understand this circuit then you can understand electronics.
@@bobcocampo it determines frequency. When you turn your car radio dial, you are changing the values of a LC circuit to the same frequency of your desired radio station.
Thanks very much for this, excellent video! To feed the parallel circuit from your signal generator did you include a series resistance? I have been experimenting with this recently and wonder if the 50 ohm output of my generator is interfering with the tank circuit. I do not always seem to get results that correlate with the relevant formula.
this would have helped me score good in electronics in when i am in bachelors 10 years back. :).. still i believe this is one of the best way of explaining LC circuit.
Hey thanks for the quick reply, changing my probe to 10x mode and adding a 110 ohm resistor produced much better results. I'll remember to double check my impedance values when making LC circuits. Thank you for your insight!
I noticed at 6:20, you mentioned that the current flowing through a parallel LC circuit is the sum of the current flowing through the L and the C. I realize that this is just a back to basics explanation, but to add a "dose of reality" and peel back one more layer of the onion, so to speak, at resonance, the current flowing through the LC circuit is only a small fraction of the current flowing through either the L and the C. Most of the current is bouncing around "in the tank", and only a small current is needed to keep the tank active. This is key for power factor correction for large induction motors, such as blower motors or compressors in HVAC units. For additional explanation, see th-cam.com/video/zVOibkXeZs8/w-d-xo.html.
Great explanation. I have seen several but this one is the best so far. Could not ask for more. My marks would have been much higher if you were instructing.
when calculating the output power of an LR , LC, or LCR circuit the formula is V X LR = Wattage? V X LC = wattage? Because if you apply an AC waveform at a certain peak/peak voltage how can you calculate the outputs true power, reactive power VAR, absolute power VA of LR, LC, LCR networks?
Could you put some figures to the frequencies, voltages and currents involved, and as someone else has asked, do a video on designing the inductance and capacitance values for a given resonance please? In particular I am interested in how to decide on the the value of capacitance against inductance, as there are many variables that seemingly give the same resonant frequency. Thanks Alan, great video again!
The Potential difference of the capacitor or the potential difference of the inductor is what is causing the time/phase delay. A Resistor doesn't have a potential difference on both sides of the resistor component but when you apply a voltage/current to it but when applying a voltage/current to a capacitor or inductor the potential difference takes TIME or a time interval for the potential different to be ZERO or equal on both sides of the component . This Potential difference is what is causing the phase angle?
Thanks a lot ! This video helped me ! I have a question, it seems like you made a home-made frequency generator (who is powering the LC circuit)... Could you tell me how is it made ? (I'm planing to make a high power frequency generator to power a big LC circuit) Thank you.
hi there im using an owon scope mod 6062,but cannot reassembly this experiment,...using .1 microfarad cap ,and 150 mh inductor..and 1300 hertz freq...do i need a 3 channel input scope?
You can use a two channel scope but will have to do the math yourself.. Measure the peak-peak for each channel and find the frequency where they are equal.
Humm...deciding the ratios of inductance and capacitance (out of the many possible combination's that would be resonant at a specific frequency) - would be a good point to begin to talk about the "Q" of these combo's?
So does the power source for the circuit HAVE to be AC? What about a circuit that uses a standard 9v battery? How would you make the LC circuit continually resonate then? Would you have to first create an oscillating dc circuit, like PWM?
Hi, I love your video series: the format if a piece if well-explained theory followed by a simple practical demonstration is really great. Thanks for making these available...I'm really enjoying working my way through the ones you have already done and looking forward to new ones. A question about this particular video: am I right in thinking that this will only work if the values if L and C are the same (e.g. 220nH and 220nH)? This is the only way that the impedences will be equal at the freq?
👍Thank you sir. sir i have this doubt for very long time. if parallel LC Resonant circuit will not consume any current. the intermediate frequency transformer and rf transformer how does it work? it is like a (primary parallel LC circuit) with secondary.(vu2knd). sir your answer very very valuable information for hams and RF community.
8:00 so this would make the 2nd circuit a band-stop filter would it? At resonance, the parallel circuit could short to ground maybe through a resistor.
Try to make a back to basics of capacitors and inductors "complex impedance" because when a variable DC voltage is applied to either a capacitor or inductor their complex impedance changes, why does it change? I think they use this often in oscillator circuits and tuning circuits to change the pitch & resonance frequency by using a variable DC bias voltage to vary the capacitor or inductors complex impedance. What would be the best water analogy for a capacitors and inductors complex impedance?
My question is, in an antenna tuned circuit in the front end of a tube receiver, is the resonnant circuit parallel for maximum voltage to the grid or serie for maximum voltage?
hello! Thanks for your video. I would have a question : how is it possible that with experimenting with simple, basic oscillators (like colpitts LC) sometimes i get a frequency like exactly 68.5 MHz even if the oscillator is supposed to make something like 10 kHz for example? And it happens with different oscillators! Is it something like an external signal strong enough to be captured? I don't understand it, And it looks too perfect (I can recognise my own signal by this , they are not perfect because of my cables and not exact components etc.) .
Many circuits are subject to parasitic oscillation - oscillation due to the parasitic capacitance/inductance of the components themselves. Check out my video on ferrite beads which includes an audio oscillator that breaks into very high frequency oscillation.
still learning all this stuff.. see if iam on track here.. say for regen or sw rx. the LC say resonates at 5mhz. the radio will then rx above and below 5mhz? or it sums or something.. i build or try to regens and clones of old kits. like the ten tec 1253 i think it is.. the multi band kit from few years back... iam havin a issue wraping my head around this i think lol ..ps edit.. should i use a freq gen to messure the LC ? i see some using a function gen..
Thank you so much, This creates a question about my hand crank generator. I used a four diode bridge rectifier with a capacitor to smooth out the AC and now I wonder if I should add an inductor....? Will the inductor stop all current? or will it effectively and totally smooth out the AC for a good clean DC. Any help appreciated Harold PS. You said the cancel each other out like an open circuit but then you said it would be good for filters?
No need for the inductor in your case of power generation. For the filter - picture the LC tank circuit in parallel with a load. At the resonant frequency, it looks like an open, so the load gets all of the signal. At other frequencies, the LC will shunt some of the signal away from the load. This is one possibly implementation.
Alan. i tried to replicate your experiment in LC resonance...when i did the math in my scope..saw the two signals subtracting from each other...the coil minus the cap. voltage as a matter of fact was perfect....so far ok..but when l increased or lower the frequency could not see the increasing or decreasing efects on this two volatages as i expected and supose to happen..using an fg 085 sig gen , and a two channel owon ds 6062 scope..do i need another conection or something else to do this test? apeciate you help thanks...kp4 bp.....Ruben...
Great video, Alan! I'm curious, since it's possible to have a series LC circuit be a band-pass filter, and a parallel LC circuit doing the same, which is the preferred configuration? My instinct says a parallel LC circuit, but I can't back that up.
It really depends on the surrounding circuitry and how the resonant impedance is utilized. The parallel LC will look like a high impedance at resonance and the series LC will look like a low impedance at resonance.
DC resistance of the coil will limit the AC current flow through it.. All wire has resistance, unless it is in a liquid nitrogen bath, then the wire will have near zero resistance.
Thanks, but what I don't understand fully is that when, for example, you're tuning a circuit and trying to change the resonance frequency, you do it with a variable capacitor (or so I read). Would this action not offset the balance between capacitive and inductive impedances (Xc not = Xl) and not cause a resonance at all?
No - all it means is that Xc = Xl at a different frequency, which is the desired result. Mathematically, *every* combination of L and C has a resonant frequency. In practice, some combinations are impractical.
Very good. So if I want to select L and C for a given resonant frequency, is there a formula to determine the ideal values for L and C without resorting to trial and error ? Thanks.
The formulas are on page 2 of the video notes: www.qsl.net/w2aew/youtube/LC_Resonance.pdf There are an infinite combinations of L and C for any given resonant frequency. Usually you'll start with a capacitor or inductor that is common or that you have on hand, and then calculate the remaining component value. If that results in an unreasonable or unrealistic component value, then adjust your first selection and repeat.
Hi, great video. I only have a square wave generator and an oscilloscope with one channel. I would like to use is to find the Inductor value. Is it possible? Thanks a lot.
Another great one. I still don't understand why I keep finding very low value inductors in logic level communication circuits (usb x, I^2C, etc.) Is it just to stop hot plug spikes? I don't get it.
In the case where you have two coils to transmit energy (like a wireless charger), What consequences does it have on the yield when you increase your capacity ? Is there any advantage to have a great C and a smaller frequency or the oposite (If the inductance is the same) ? It would help me a lot :) (and sorry for my english)
Hi there. i was wondering, that instead of a signal generator, if i hook up an antena will i be able to resonate the circuit at a particular frequency to get a signal? also do i need to amplify the signal before i channel it through the tank circuit? i am working on a radio controller right now and i really need to complete it before my holidays are over.please reply soon. and nice work (^_^)
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You are amazing! Showing the hand drawn diagrams, the actual circuits and the scope! All in 10 minutes!
Thank you SO MUCH for this! I've been struggling to understand resonance and none of the other videos I have watched have cleared it up for me.
I studied 3 years of technical school and 5 years of engineering and never saw so better explanation.
Don't know why to spend years doing calculations when a practical lesson like this one sace years of time
You've made me do one thing my teacher was not capable to do through the whole semester: make me think over what we were studying. Thank you for that, honestly.
Love your video, perfect explanation, using the scope and the theory! I’ve been studying this for years and have never had such a clear and concise explanation. Thank You!!
Where were YOU when I was in college? :))
God bless you.
I hope as many students as possible find this channel.
Watch many of your videos and they are amongst the very best - thank you. Despite the excellence of your material I find it useful to replicate your demonstrations - there is even more learning to be found! This one for example - at resonance the source is effectively shorted and mine doesn't like that. Also haven't found a way to hide a trace on the scope that is used in math but not needed on the display. Excellent skill building experiments. Brilliant. I encourage anyone to try reproducing what seem at first to be simple circuits.
I've just started looking at tuned circuits as part of prep for a licence exam and found this a very helpful perspective to understand why the basic LC circuits behave as they do.
My "teacher" in Uni made a complete dogs dinner of this despite having all the resources of a modern Uni at his disposal.
You totally nailed it with some graph paper, a scope and $0.000000002 in components.
Maybe you should share this video with your UNI teacher, and your fellow students!
I never got this intuitive view of series and parallel resonance when I studied circuit analysis. Thanks so much for this great lecture.
Since a long time i am searching for hardcore electronics hardware vedios, your vedio are amazing keep making vedios on more complex electronics hardware
That's awesome I was struggling to understand why one lagging the other mattered and then you went "above and beyond" the resonant frequencies skewing and squashing the waveform. Outstanding, I have the next step ahead of me!
This guy has some of the best instructional videos on TH-cam. Very well explained and to the point.
Excellently explained, finally understood this concept: at resonant frequency the resistance/impedance is zero, effectively acting as a short! Perfect!!!
I agree - pure gold!
By far the best and clearest videos on these subjects on youtube.
To the above suggestion on filters I wish to suggest adding 'back to basics' videos on the following:
1. Ground - difference between DC/AC circuits, floating ground, ground loops and how to avoid them, best practices and the how and where to use isolation transformers and how they work
2. RC oscillators.
3. Which capacitor/inductor types are good for which applications and which values to use.
Awesome video. Your explanation is loaded with detail but yet very simple to understand. The series LC circuit is exactly what we use on the railroad for our crossing circuits. Each RR crossing has it's own frequency and there is a series LC just as you described at either end of the approach to terminate the circuit and define the limits of the approach. This allows multiple crossing approach circuits to be stacked upon one another, each with it's own frequency and tuned termination shunts (the series LC). It also allows our DC signaling pulses to pass through unimpeded.
4:20 Seeing this frequency dependancy of impedance in an oscilloscope is just soo cool.
Excellent video. As a lapsed electrical engineer it makes me want to watch a few more. I was intrigued by the pencil drawings. I never thought that they would work so well in a video, but they do.
Aww haa! Now I understand the why of the left channel fault on a tape machine I repaired. I knew something was off with the left side bias trap by intuition. After looking at your video, I was able to confirm that the bias trap had drifted off frequency by 12KHz. Really cool stuff you've offered. Thanks. Now, as to why I've chosen tape machine repair as a hobby, I'm afraid there's no help for it. Actually, I try to repair everything :-)
possibly the best video demonstration of a LC resonance.
Your presentation is short and sweet for quick review. It is easy to follow. Thank you.
In the parallel circuit, you could put 1 Ohm resistance in series with L and C (on the ground side) to show the phase relation between the currents. Once again, they are always out of phase and resonance is when their amplitudes are equal -- V/X_L = I_L = I_C = V/X_C. Cross multiply and cancel V to see X_L = X_C once again at resonance.
Yes sir! This helped out a lot having your explanation coupled with the oscilloscope and your diagrams. This tied some loose ends in the education. Thank you!
Clarity , instruction and demos are simply fantastic. Thank you so much . Had trouble fully conceptualizing rc and resonances until I saw this. I love it . I would love to understand more about the application. You mentioned at resonance, useful things can be done . Would love know more about this is used in application . Thank you . Subscribed, and liked
The "open circuit" scenario gives me a better perspective of antenna traps... thanks Alan.
Thank you for this. It's the clearest, most intuitive explanation I've seen.
This is one great explanation of LC circuits! Just the right mix of science theory and experimentation.
Very interesting tutorial lesson of the series and parallel connection of capacitor and inductance circuits. Thanks for the nice video.
Looked forward to watching this video all day! Thanks!
I love this channel ... this helps us to learn theory and working model at the same time ... Thank you so much.
clearest explanation on RC resonance circuit. beat textbooks.
Studying for my physics lab, this was really helpful. Thanks a lot.
Thank you Allen. I thought I've watched all your videos but every once in while a "new" old one pops up. :/ I've been playing with electronics my whole life, Science Fair kits, fixing VCRS, resoldering broken jacks, I even wanted to be go to school for EET) but it wasn't until I started watching your videos that things clicked. I love your back to basics keep them coming :). Btw. Your lucky I'm not your next door neighbor I'd be bugging you everyday.
There is a link to a complete index to all of my videos on the main channel page. You can use this to keep track of the ones you've watched.
I'd like to see a series on LC circuits and filters. Fundamentals to radio building. Excellent work!
Very very helpful in understanding Series and Parallel LC circuits! I'm excited to get home this evening and build one on my breadboard.
Thank you. Im just started getting into RF and didn't understand how the local oscillator selected the frequency from the antennae in the tuner circuit. I understood that the local oscillator had a resonant frequency it oscillates at but i didn't see how it discriminated out all the different incoming frequencies from the antennae. Now I think I see that the parallel LC circuit will short the unwanted frequencies to gnd and effectively pass-through the selected frequency along the signal path by virtue of it effectively acting as an open for that frequency. I'm sure I don't fully understand it still but this was helpful. Thanks.
That is part of it (tuning the front-end bandpass filter), but the main thing that involves the local oscillator is the mixing circuit. This video might help: th-cam.com/video/Vf06HSR4LdY/w-d-xo.html
Amazing explanation. Thank you!!
I can not express the importance of this video for those want to learn electronics. once you understand this circuit then you can understand electronics.
What is the application in electronics?
@@bobcocampo it determines frequency. When you turn your car radio dial, you are changing the values of a LC circuit to the same frequency of your desired radio station.
It's a pleasure to learn from your videos! Thank You!
Thanks very much for this, excellent video!
To feed the parallel circuit from your signal generator did you include a series resistance? I have been experimenting with this recently and wonder if the 50 ohm output of my generator is interfering with the tank circuit. I do not always seem to get results that correlate with the relevant formula.
this would have helped me score good in electronics in when i am in bachelors 10 years back. :).. still i believe this is one of the best way of explaining LC circuit.
I was hoping to see the phase shifts above and below resonance
Hey thanks for the quick reply, changing my probe to 10x mode and adding a 110 ohm resistor produced much better results. I'll remember to double check my impedance values when making LC circuits. Thank you for your insight!
very interesting to note that parallel acts like an open circuit but yet a very real a/c field exists.
Excellent method for finding resonance.. thank you for posting!
Great job Alan. I love these basics videos! Keep up the great content!
Very useful video for understanding the concept of dual resonant solid state teslacoils
Thanks for a another brilliant video, pure gold. As a sugestion how about a 'back to basics' series on filter circuits?
I noticed at 6:20, you mentioned that the current flowing through a parallel LC circuit is the sum of the current flowing through the L and the C. I realize that this is just a back to basics explanation, but to add a "dose of reality" and peel back one more layer of the onion, so to speak, at resonance, the current flowing through the LC circuit is only a small fraction of the current flowing through either the L and the C. Most of the current is bouncing around "in the tank", and only a small current is needed to keep the tank active. This is key for power factor correction for large induction motors, such as blower motors or compressors in HVAC units. For additional explanation, see th-cam.com/video/zVOibkXeZs8/w-d-xo.html.
Great explanation. I have seen several but this one is the best so far. Could not ask for more. My marks would have been much higher if you were instructing.
thanks a lot for these sir! Back to Basics series are amazing!
This reminds me a bit of Uncle Doug. Classic. Thanks.
when calculating the output power of an LR , LC, or LCR circuit the formula is V X LR = Wattage? V X LC = wattage? Because if you apply an AC waveform at a certain peak/peak voltage how can you calculate the outputs true power, reactive power VAR, absolute power VA of LR, LC, LCR networks?
Could you put some figures to the frequencies, voltages and currents involved, and as someone else has asked, do a video on designing the inductance and capacitance values for a given resonance please? In particular I am interested in how to decide on the the value of capacitance against inductance, as there are many variables that seemingly give the same resonant frequency. Thanks Alan, great video again!
The Potential difference of the capacitor or the potential difference of the inductor is what is causing the time/phase delay. A Resistor doesn't have a potential difference on both sides of the resistor component but when you apply a voltage/current to it but when applying a voltage/current to a capacitor or inductor the potential difference takes TIME or a time interval for the potential different to be ZERO or equal on both sides of the component . This Potential difference is what is causing the phase angle?
Thanks a lot ! This video helped me !
I have a question, it seems like you made a home-made frequency generator (who is powering the LC circuit)... Could you tell me how is it made ? (I'm planing to make a high power frequency generator to power a big LC circuit) Thank you.
hi there im using an owon scope mod 6062,but cannot reassembly this experiment,...using .1 microfarad cap ,and 150 mh inductor..and 1300 hertz freq...do i need a 3 channel input scope?
You can use a two channel scope but will have to do the math yourself.. Measure the peak-peak for each channel and find the frequency where they are equal.
@@Liviu75tx
Awesome and effective explanation. Thanks.
Humm...deciding the ratios of inductance and capacitance (out of the many possible combination's that would be resonant at a specific frequency) - would be a good point to begin to talk about the "Q" of these combo's?
Exlent sir wow, I never understood before u, thanks thanks thanks
So does the power source for the circuit HAVE to be AC? What about a circuit that uses a standard 9v battery? How would you make the LC circuit continually resonate then? Would you have to first create an oscillating dc circuit, like PWM?
An LC circuit won't oscillate on it's own. You'd need to "ping" it with a signal to cause it to ring (much like striking a bell).
Hi, I love your video series: the format if a piece if well-explained theory followed by a simple practical demonstration is really great. Thanks for making these available...I'm really enjoying working my way through the ones you have already done and looking forward to new ones.
A question about this particular video: am I right in thinking that this will only work if the values if L and C are the same (e.g. 220nH and 220nH)? This is the only way that the impedences will be equal at the freq?
This is really helpful thank you. I am thinking what happens in a mixture of series and parallel? I will have to get a scope.
Great lesson!
cheers from INDIA.
can you pls make a video on foster seeley FM demodulator.
your explanation is really great and is enhancing my knowledge.
thank you
when the impedances are equal, does it not lead to voltage magnification ?
👍Thank you sir. sir i have this doubt for very long time.
if parallel LC Resonant circuit will not consume any current.
the intermediate frequency transformer and rf transformer how does it work?
it is like a (primary parallel LC circuit) with secondary.(vu2knd).
sir your answer very very valuable information for hams and RF community.
awesome. i like your explaining style very much.
By this logic, wouldn't a resonant transformer appear to the power supply as a "short circuit" when opperated at the resonant frequency?
Thank you!
Cheers,
Dave
8:00 so this would make the 2nd circuit a band-stop filter would it? At resonance, the parallel circuit could short to ground maybe through a resistor.
Thanks...now i really understand how a lc circuit works....
Thank you very much. Very clear explanations. Have subscribed the channel.
Try to make a back to basics of capacitors and inductors "complex impedance" because when a variable DC voltage is applied to either a capacitor or inductor their complex impedance changes, why does it change? I think they use this often in oscillator circuits and tuning circuits to change the pitch & resonance frequency by using a variable DC bias voltage to vary the capacitor or inductors complex impedance. What would be the best water analogy for a capacitors and inductors complex impedance?
My question is, in an antenna tuned circuit in the front end of a tube receiver, is the resonnant circuit parallel for maximum voltage to the grid or serie for maximum voltage?
Since the grid is high impedance, the tuned circuit would be in parallel to generate the highest voltage for the grid to "sense".
TKS U. By the way excellent video! 73
Wonderful amazing explanation simple too!
Thank you...
how are you feeding the circuit the frequency? are you using function generator at 4:16 ?
hello! Thanks for your video. I would have a question : how is it possible that with experimenting with simple, basic oscillators (like colpitts LC) sometimes i get a frequency like exactly 68.5 MHz even if the oscillator is supposed to make something like 10 kHz for example? And it happens with different oscillators! Is it something like an external signal strong enough to be captured? I don't understand it, And it looks too perfect (I can recognise my own signal by this , they are not perfect because of my cables and not exact components etc.) .
Many circuits are subject to parasitic oscillation - oscillation due to the parasitic capacitance/inductance of the components themselves. Check out my video on ferrite beads which includes an audio oscillator that breaks into very high frequency oscillation.
Nice video. I need a 2KHz sine wave oscillator to drive a car buzzer. Do you know if there is an IC out there I can use other then 555?
still learning all this stuff.. see if iam on track here.. say for regen or sw rx. the LC say resonates at 5mhz. the radio will then rx above and below 5mhz? or it sums or something.. i build or try to regens and clones of old kits. like the ten tec 1253 i think it is.. the multi band kit from few years back... iam havin a issue wraping my head around this i think lol ..ps edit.. should i use a freq gen to messure the LC ? i see some using a function gen..
Thank you so much, This creates a question about my hand crank generator.
I used a four diode bridge rectifier with a capacitor to smooth out the AC and now I wonder if I should add an inductor....?
Will the inductor stop all current? or will it effectively and totally smooth out the AC for a good clean DC.
Any help appreciated
Harold
PS. You said the cancel each other out like an open circuit but then you said it would be good for filters?
No need for the inductor in your case of power generation.
For the filter - picture the LC tank circuit in parallel with a load. At the resonant frequency, it looks like an open, so the load gets all of the signal. At other frequencies, the LC will shunt some of the signal away from the load. This is one possibly implementation.
Alan. i tried to replicate your experiment in LC resonance...when i did the math in my scope..saw the two signals subtracting from each other...the coil minus the cap. voltage as a matter of fact was perfect....so far ok..but when l increased or lower the frequency could not see the increasing or decreasing efects on this two volatages as i expected and supose to happen..using an fg 085 sig gen , and a two channel owon ds 6062 scope..do i need another conection or something else to do this test? apeciate you help thanks...kp4 bp.....Ruben...
giving you a thumbs up mister!
Great video, Alan! I'm curious, since it's possible to have a series LC circuit be a band-pass filter, and a parallel LC circuit doing the same, which is the preferred configuration? My instinct says a parallel LC circuit, but I can't back that up.
It really depends on the surrounding circuitry and how the resonant impedance is utilized. The parallel LC will look like a high impedance at resonance and the series LC will look like a low impedance at resonance.
DC resistance of the coil will limit the AC current flow through it.. All wire has resistance, unless it is in a liquid nitrogen bath, then the wire will have near zero resistance.
Excellent tutorial on the topic! I really enjoy your videos. Thanks!
When I take over the world historians will point to this video as the catalyst for the expression of my evil genius.
Thanks, but what I don't understand fully is that when, for example, you're tuning a circuit and trying to change the resonance frequency, you do it with a variable capacitor (or so I read). Would this action not offset the balance between capacitive and inductive impedances (Xc not = Xl) and not cause a resonance at all?
No - all it means is that Xc = Xl at a different frequency, which is the desired result. Mathematically, *every* combination of L and C has a resonant frequency. In practice, some combinations are impractical.
***** Hmmm, okay, I think I got it now. Thanks.
nice and clear, thanks doc!
Nicely explained video. Thank You
Very good. So if I want to select L and C for a given resonant frequency, is there a formula to determine the ideal values for L and C without resorting to trial and error ? Thanks.
The formulas are on page 2 of the video notes:
www.qsl.net/w2aew/youtube/LC_Resonance.pdf
There are an infinite combinations of L and C for any given resonant frequency. Usually you'll start with a capacitor or inductor that is common or that you have on hand, and then calculate the remaining component value. If that results in an unreasonable or unrealistic component value, then adjust your first selection and repeat.
I’d be curious to see if one could find the resonant frequency of aTesla coil using this method
Great video !
Nice demo. Thanks!
Very nicely explained
How come when I do this with calculated value for 35khz of 1.2uh and 2.2uf I get 9 megahertz vale for the signals to do what you did??
You may want to check your math. A 1.2uH inductor and a 2.2uF capacitor will have a calculated resonant frequency of 98kHz.
Hi, great video. I only have a square wave generator and an oscilloscope with one channel. I would like to use is to find the Inductor value. Is it possible? Thanks a lot.
Sure - check out this video:
th-cam.com/video/74fz9iwZ_sM/w-d-xo.html
Another great one. I still don't understand why I keep finding very low value inductors in logic level communication circuits (usb x, I^2C, etc.) Is it just to stop hot plug spikes? I don't get it.
Those are usually acting as fuses. They protect the circuits from being abused with voltage sources. The coil will burn out under unusual currents.
In the case where you have two coils to transmit energy (like a wireless charger), What consequences does it have on the yield when you increase your capacity ? Is there any advantage to have a great C and a smaller frequency or the oposite (If the inductance is the same) ?
It would help me a lot :) (and sorry for my english)
Hi there. i was wondering, that instead of a signal generator, if i hook up an antena will i be able to resonate the circuit at a particular frequency to get a signal? also do i need to amplify the signal before i channel it through the tank circuit? i am working on a radio controller right now and i really need to complete it before my holidays are over.please reply soon.
and nice work (^_^)