A neat explanation for the behavior of capacitors in series and parallel i picked up in trade school: Two or more capacitors in parallel act as one capacitor with the sum area of plates of the individual ones, therefor increasing capacitance. Two or more capacitors in series act as one capacitor with the sum distance of the plates of the individual ones, therefor decreasing capacitance. Understanding this helped me quite a lot.
Im really glad you are expanding your video range from repair into more theory and practical demo, as its a great help to understand what is happening in a circuit and how replacement parts, in this case capacitors, may or may not have an effect if they are of a different specification. Also, what may have gone wrong or how we can improve a circuit. Then reading the comments gives a further education into how these are used in equipment I've yet to have a play with. 😂 I'm loving it 😊 Keep them coming.
Wow! So amazing to have found your channel. I've played with DC my whole life, but not much AC. I've been wanting to learn more about how AC behaves in circuits and your channel is Gold. Interestingly enough, I have equipped my lab with almost the exact same equipment you are using, so even more valuable since I can just follow along more easily with the settings. Instantly subscribed. Thank you very much.
I asked for common circuits in your last video and you published exactly that a couple of days later. I wonder if it will work again? I'm with you, and the practical explanations are good. I'm still a step away from understanding the practical uses though. I can just about guess some of them on the AC side, for uses like smoothing, noise reduction and rectification in a power supply. But capacitors are littered about all DC circuits too. I see the timing/delay function as you demoed it, but I can't second-guess the practical use-case for it.
The only thing i would take issue with is the voltage at the junction of capacitors in series. The reason you saw zero voltage is because your meter is resistive and discharged the capacitor. If you had a purely capacitive meter you would have seen the true voltage at the junction. You can prove this by connecting the junction to the gate of a mosfet, if the voltage is zero the mosfet will stay off. If it is not zero (and above the gate threshold) the mosfet will turn on. Obviously the capacitor values have to be large enough such that the capacitive effect of the mosfet does not overwhelm them.
Oooohhh now this sounds like an experiment for the next live stream... of course the mosfet will have to be connected to something 'interesting' to prove the point one way or another. @theelectronicschannel Sunday 21st Jan 17:00 let's have some fun and prove ChrisHartley right or wrong.. Possibly with explosive consequences
@@LearnElectronicsRepair Rather than a simple MOSFET which will tell you very little I would suggest using a FET-input op-amp as a simple voltage follower. With the amp you can actually measure the DC voltage and you'll have much lower additional capacitance than you'll get from anything but a tiny MOSFET. Bandwidth will be only moderate with most common FET op-amps. The input bias current of a FET amp will be lower than the leakage current of the breadboard. If you want a very low leakage node, solder the parts together and them hang in free air.
in the circuit at around 14:30: No matter how high the frequency is set, the voltage across the resistor will always _appear_ to be of lower magnitude than the applied signal when small capacitances are used. There is significant capacitance at the tip of an oscilloscope probe. A high-quality probe with 10:1 attenuation will typically have a tip capacitance of 10 to 15 pF. If a non-attenuating ordinary probe is used the capacitance can be several tens of picofarads. With a 47 pF series capacitor, at best about 80% of the signal will actually be apparent on the scope simply due to the capacitive divide formed. (This is why you should never use a x1/x10 switchable probe at x1 except in circumstances where you clearly understand the consequences.) For very low capacitance an active ("FET") probe is required. Tip capacitance of 1 to 2 pF is fairly common. A good quality FET probe probably will cost more than the oscilloscope used in the video. Where low resistance can be tolerated, "500 ohm" probes can be used for low capacitance and may be cheaper. A decent 500 ohm probe with 1.5 pF tip capacitnce might be in the range of 500-600 Euros.
Yes me too. As my interest in the video increases so does the frequency of adds. Yet as the amplitude of the add increases my interest goes down.😂 They do kick in at some most inopportune times. 'So what happens if we ... buy some home insulation.' Grrrr
I’m wondering if someone can explain a process to pick a replacement capacitor. I have a 🔊 amplifier that I’m working on, it has two capacitors at the speakers out ports that completely fried and disappeared. I managed to test 5v . Not too sure what I need from there
How does a capacitor fit into your "three uses for capacitors" when they are used in audio tone circuits such as "bass, midrange and high" on audio amplifiers or stereo equipment? Audio is a AC waveform that fluctuates both in amplitude and in frequency yet capacitors are used across potentiometers to alter the perceived sound.
Audio tone circuits use coupling and bypass capacitors, and take advantage of the fact the different value capacitors react to different frequencies, as I demonstrated. They don't use the capacitor in any other way 😉
@@LearnElectronicsRepair I guess what's confusing me is your explanation of coupling which made it sound like it works by removing DC and passing AC. As a tone altering device DC isn't part of the equation. (Or is it?) I keep seeing others adding Impedance, inductance, and reductance and reactance words into the mix which further clouds the waters as I try to understand exactly what's happening in these circuits.
Which video has the explanation for why the ripple gets worse as the frequency is increased, that you asked at the end of this video? The next video is about induction..?
Hi I’m following your channel, and even though I am a qualified service electrician, I’m a but rusty! But I have one problem though!!! For some reason, everyone I have seen seems to teach the capacitor as “intelligent “… Knowing the difference of AC and DC…??? And that pussels me greatly!!! The symbol of a capacitor, show that it is “open circuit”, and thus blocks any current !!! YES. Apparently it leads AC, but that’s because of the nature of the AC… positive one period, negative the next, thus leading to the capacitor getting charged one way one cycle, and the other way the next cycle, leading to the impression that it “leads” AC! So, am I right or what 😃😎
And for those of us who started our electronics journey by building a crystal set, don't forget that another use for capacitors is in radio tuning circuits.
I design/build guitar fx pedals.... guitar pickups are AC and the input and output caps are used to allow more or less bass frequencies in/out of the circuit (in the audio path, i mean)
@Blinkerd00d Guitar pickups are not "A/C". They are coils (with a solid metallic core). The movement of the string through the coil's field induces a current in the windings of the coil. Because the string is vibrating one way then the other way, the current generated is A/C. So, the pickup "picks up" A/C; is not A/C itself.
@@markanderson2904 I was simplifying my explanation as to not be pedantic.... pickups do indeed transfer string movement into a small AC voltage, this is referred to as electromagnetic induction. In short, we are both correct.
Your plugs at home are not 'AC', they are simply metal contacts connected to a transformer. An alternating current is induced in the second winding of the coil, which causes an alternating current to occur when the plug's circuit is closed. Pedantry.
So the value of a capacitor and AC frequency are linked, so that goes some way to explaining why a variable capacitor is used to tune a radio into a specific frequency.
Yes. You will note that the tuning circuitry is an LC circuit , inductor and capacitor. Also note that an LC circuit may be used on the output of a rectifier to smooth the DC output. It's when it's used on an A/C line that it becomes resonant circuit.
I am a bit confused now. I am a total beginner but am following this beginners course from the first video. I was OK until this video and the reason are these two machines. Oscilloscope and a signal generator. What are they, what is their purpose? How can the AC wave not go below zero? I thought that is the AC nature and below zero is the electricity going in the opposite direction? Is there another video that we are supposed to watch before this one to understand better (apart from the ones in this playlist) please?
20:13. I'm here to definitely learn. Major importance thing you didn't say is resistance RESISTANCE. You didn't say the resistance of the circuit which would be the input of the scope because that changes the frequency please make one showing that. Because that's what I've been trying to research for a long time and no video shows it. Love Ya Like A Brother But YOU GO A Bit TO Slow And I END up drifting away and can't stay focused olIf at all possible GO a talk a bit faster be the bomb
6:31 You were looking for "That's what she said," right? I'm sorry, but she didn't say that. She said "You keep telling yourself that." :p That's a fairly chunky transformer though.
The end question; This wouldn't happen if you had a perfect capacitor and circuit board. At higher frequencies, the small internal resistance and the inductance from the leads and the breadboard start to have a larger affect.
I don't understand why oscilloscope manufacturers do not use Primary Colours for their traces. Red, Yellow Green, Blue, "Purple" and White are perfectly acceptable.
@@markanderson2904 IMHO they should use, in order of brightness/contrast against the black screen, White, Yellow, Cyan. The primary colours are all decreasing in brightness in the order of Green, Red, Blue. Or at least that is how our eye or possible our brain perceives them. Feel free to discuss...
The answer to the question the end is that electrolytic caps perform very poorly at higher frquencies. They have high impedance at high frequency. eg ceramic are good at hf.
Reactive impedance is the simple reason. as the frequency rises the reactive impedance also increases so the higher value capacitor can't react fast enough to do its job. gets even MORE interesting when and IF you delve into resonance in circuits. have seen MANY an amp that suffers from that problem. resonance gets interesting when you add coils and transformers.@@LearnElectronicsRepair great series though, wish i had something like it when i first started learning electronics, but sadly there was no such thing as the internet back then, so TH-cam want even a dream. lol
A neat explanation for the behavior of capacitors in series and parallel i picked up in trade school:
Two or more capacitors in parallel act as one capacitor with the sum area of plates of the individual ones, therefor increasing capacitance.
Two or more capacitors in series act as one capacitor with the sum distance of the plates of the individual ones, therefor decreasing capacitance.
Understanding this helped me quite a lot.
Im really glad you are expanding your video range from repair into more theory and practical demo, as its a great help to understand what is happening in a circuit and how replacement parts, in this case capacitors, may or may not have an effect if they are of a different specification. Also, what may have gone wrong or how we can improve a circuit.
Then reading the comments gives a further education into how these are used in equipment I've yet to have a play with. 😂
I'm loving it 😊 Keep them coming.
10:02 Where did you get that lovely breadboard that makes the windows USB-plugged-in sound, when a component is inserted? 😅
Wow! So amazing to have found your channel. I've played with DC my whole life, but not much AC. I've been wanting to learn more about how AC behaves in circuits and your channel is Gold. Interestingly enough, I have equipped my lab with almost the exact same equipment you are using, so even more valuable since I can just follow along more easily with the settings. Instantly subscribed. Thank you very much.
Loving this series , I'm learning so much!
Your videos have been very helpful to many electronics enthusiasts around the world. Thank you, and I wish you good health always.
A fan from Vietnam.
Excellent video as always! I am learning a lot that has been hard to grasp in the past. Thank you!
Brilliant very good demo please more of this explains a lot thanks Richard
I asked for common circuits in your last video and you published exactly that a couple of days later. I wonder if it will work again?
I'm with you, and the practical explanations are good. I'm still a step away from understanding the practical uses though. I can just about guess some of them on the AC side, for uses like smoothing, noise reduction and rectification in a power supply. But capacitors are littered about all DC circuits too. I see the timing/delay function as you demoed it, but I can't second-guess the practical use-case for it.
Very valuable video to me. Thank you!
I though have to redo your experiments on my own to understand it fully.
The only thing i would take issue with is the voltage at the junction of capacitors in series.
The reason you saw zero voltage is because your meter is resistive and discharged the capacitor. If you had a purely capacitive meter you would have seen the true voltage at the junction.
You can prove this by connecting the junction to the gate of a mosfet, if the voltage is zero the mosfet will stay off. If it is not zero (and above the gate threshold) the mosfet will turn on. Obviously the capacitor values have to be large enough such that the capacitive effect of the mosfet does not overwhelm them.
Oooohhh now this sounds like an experiment for the next live stream... of course the mosfet will have to be connected to something 'interesting' to prove the point one way or another. @theelectronicschannel Sunday 21st Jan 17:00 let's have some fun and prove ChrisHartley right or wrong.. Possibly with explosive consequences
@@LearnElectronicsRepair
Rather than a simple MOSFET which will tell you very little I would suggest using a FET-input op-amp as a simple voltage follower. With the amp you can actually measure the DC voltage and you'll have much lower additional capacitance than you'll get from anything but a tiny MOSFET. Bandwidth will be only moderate with most common FET op-amps.
The input bias current of a FET amp will be lower than the leakage current of the breadboard. If you want a very low leakage node, solder the parts together and them hang in free air.
Clearest explanation I have ever seen
in the circuit at around 14:30:
No matter how high the frequency is set, the voltage across the resistor will always _appear_ to be of lower magnitude than the applied signal when small capacitances are used.
There is significant capacitance at the tip of an oscilloscope probe. A high-quality probe with 10:1 attenuation will typically have a tip capacitance of 10 to 15 pF. If a non-attenuating ordinary probe is used the capacitance can be several tens of picofarads. With a 47 pF series capacitor, at best about 80% of the signal will actually be apparent on the scope simply due to the capacitive divide formed. (This is why you should never use a x1/x10 switchable probe at x1 except in circumstances where you clearly understand the consequences.)
For very low capacitance an active ("FET") probe is required. Tip capacitance of 1 to 2 pF is fairly common. A good quality FET probe probably will cost more than the oscilloscope used in the video. Where low resistance can be tolerated, "500 ohm" probes can be used for low capacitance and may be cheaper. A decent 500 ohm probe with 1.5 pF tip capacitnce might be in the range of 500-600 Euros.
Very nice demonstration of the relation between frequency and capacitance value btw ads are in shape in this video i got a total of 8 ads lol
Yes me too. As my interest in the video increases so does the frequency of adds. Yet as the amplitude of the add increases my interest goes down.😂
They do kick in at some most inopportune times. 'So what happens if we ... buy some home insulation.' Grrrr
£8 a month and it all goes away and Richard sees the correct revenue for the AD, win-win.
excellent richard thank you
Heya, the basic of capacitors I already untherstood and now I untherstand coupling and decoupling
35:38 - Why is the input voltage taking longer to reach peak? I thought we would only see the effect on the output voltage?!
Could you not use a signal generator for the ac voltage ?
Oh! You did lol. :)
Thank you for the didactic elucidation of the dielectric element, I really got a charge out of it!😄
I’m wondering if someone can explain a process to pick a replacement capacitor. I have a 🔊 amplifier that I’m working on, it has two capacitors at the speakers out ports that completely fried and disappeared. I managed to test 5v . Not too sure what I need from there
How does a capacitor fit into your "three uses for capacitors" when they are used in audio tone circuits such as "bass, midrange and high" on audio amplifiers or stereo equipment?
Audio is a AC waveform that fluctuates both in amplitude and in frequency yet capacitors are used across potentiometers to alter the perceived sound.
Audio tone circuits use coupling and bypass capacitors, and take advantage of the fact the different value capacitors react to different frequencies, as I demonstrated. They don't use the capacitor in any other way 😉
@@LearnElectronicsRepair I guess what's confusing me is your explanation of coupling which made it sound like it works by removing DC and passing AC. As a tone altering device DC isn't part of the equation. (Or is it?)
I keep seeing others adding Impedance, inductance, and reductance and reactance words into the mix which further clouds the waters as I try to understand exactly what's happening in these circuits.
Good job
Great video.
Which video has the explanation for why the ripple gets worse as the frequency is increased, that you asked at the end of this video? The next video is about induction..?
10/10 for this one. Thanks 😃
Hi
I’m following your channel, and even though I am a qualified service electrician, I’m a but rusty!
But I have one problem though!!!
For some reason, everyone I have seen seems to teach the capacitor as “intelligent “… Knowing the difference of AC and DC…??? And that pussels me greatly!!!
The symbol of a capacitor, show that it is “open circuit”, and thus blocks any current !!!
YES. Apparently it leads AC, but that’s because of the nature of the AC… positive one period, negative the next, thus leading to the capacitor getting charged one way one cycle, and the other way the next cycle, leading to the impression that it “leads” AC!
So, am I right or what 😃😎
thank you
And for those of us who started our electronics journey by building a crystal set, don't forget that another use for capacitors is in radio tuning circuits.
True
I design/build guitar fx pedals.... guitar pickups are AC and the input and output caps are used to allow more or less bass frequencies in/out of the circuit (in the audio path, i mean)
@Blinkerd00d
Guitar pickups are not "A/C". They are coils (with a solid metallic core). The movement of the string through the coil's field induces a current in the windings of the coil. Because the string is vibrating one way then the other way, the current generated is A/C. So, the pickup "picks up" A/C; is not A/C itself.
@@markanderson2904 I was simplifying my explanation as to not be pedantic.... pickups do indeed transfer string movement into a small AC voltage, this is referred to as electromagnetic induction. In short, we are both correct.
Your plugs at home are not 'AC', they are simply metal contacts connected to a transformer. An alternating current is induced in the second winding of the coil, which causes an alternating current to occur when the plug's circuit is closed.
Pedantry.
@@Tr1ploid for the win. Lol
thanks, very educational 👊
Our friend... capacitive reactance.
So the value of a capacitor and AC frequency are linked, so that goes some way to explaining why a variable capacitor is used to tune a radio into a specific frequency.
Yes. You will note that the tuning circuitry is an LC circuit , inductor and capacitor. Also note that an LC circuit may be used on the output of a rectifier to smooth the DC output. It's when it's used on an A/C line that it becomes resonant circuit.
I am a bit confused now. I am a total beginner but am following this beginners course from the first video. I was OK until this video and the reason are these two machines. Oscilloscope and a signal generator. What are they, what is their purpose? How can the AC wave not go below zero? I thought that is the AC nature and below zero is the electricity going in the opposite direction? Is there another video that we are supposed to watch before this one to understand better (apart from the ones in this playlist) please?
20:13. I'm here to definitely learn. Major importance thing you didn't say is resistance RESISTANCE. You didn't say the resistance of the circuit which would be the input of the scope because that changes the frequency please make one showing that. Because that's what I've been trying to research for a long time and no video shows it. Love Ya Like A Brother But YOU GO A Bit TO Slow And I END up drifting away and can't stay focused olIf at all possible GO a talk a bit faster be the bomb
You can always play the video at X1.25 if it's too slow for you.
It's so hard to find the correct speed, if I go faster some viewers ask me to slow down LOL
That breadboard has seen some heat lol.
6:31 You were looking for "That's what she said," right? I'm sorry, but she didn't say that. She said "You keep telling yourself that." :p That's a fairly chunky transformer though.
Nice explanation, one of the best available I would say, be interesting when you introduce ESR....cheers.
The end question;
This wouldn't happen if you had a perfect capacitor and circuit board. At higher frequencies, the small internal resistance and the inductance from the leads and the breadboard start to have a larger affect.
I don't understand why oscilloscope manufacturers do not use Primary Colours for their traces.
Red, Yellow Green, Blue, "Purple" and White are perfectly acceptable.
Why do you think that they should use (what you think are) primary colours?
@@markanderson2904 IMHO they should use, in order of brightness/contrast against the black screen, White, Yellow, Cyan. The primary colours are all decreasing in brightness in the order of Green, Red, Blue. Or at least that is how our eye or possible our brain perceives them. Feel free to discuss...
Hi Richard, you may think I'm being pedantic but It's "pico" farads not "pica" farads. 😅👍
LC. HF. FILTER CAPACITOR VERSES RESISTANCE. WHERES THAT
The answer to the question the end is that electrolytic caps perform very poorly at higher frquencies. They have high impedance at high frequency. eg ceramic are good at hf.
But why is that the case?
@@LearnElectronicsRepair
The capacitor used gets all wound up and its reactance goes to 'ell.
Reactive impedance is the simple reason. as the frequency rises the reactive impedance also increases so the higher value capacitor can't react fast enough to do its job. gets even MORE interesting when and IF you delve into resonance in circuits. have seen MANY an amp that suffers from that problem.
resonance gets interesting when you add coils and transformers.@@LearnElectronicsRepair great series though, wish i had something like it when i first started learning electronics, but sadly there was no such thing as the internet back then, so TH-cam want even a dream. lol
@@tezza3733
The question is WHY the impedance begins to rise with increasing frequency. This is not an inherent property of an ideal capacitor.
Wish you were an amateur radio operator.
Can you stop uploading videos please. I need to get some work done lol
😂😂😂😂
I need my ridiculously early morning videos to watch (listen) on my way to work. Lol
I’ve been up since 6am watching them again 🙄
I’m officially an addict 😂😂😂
Work harder!
Work smarter, not harder.
Hey, first? cool