Arnold Scwartzenager said “ any rep is a hood rep”… THIS LECTURE IS…DELICIOUS…. In high school I attended “Vocational Training” / electronics in my junior and senior years… ( 1972-1974)… and resistors, capacitors and inductors… and therefore LRC circuits …and therefore “ right triangles”…. Were…the…. Peak of our mountain tops…. I am interested in reviewing the concepts … just because…. ( and I have some old tube and transistor amps)… I can clean pots, switches and tube sockets all day… but eventually we need to remember how to trace volts … know what to expect …and how to do it safely when sometimes there is 400 volts in the circuit. Again… GREAT…SERIES…of lectures… ( one of my first benchmarks when I saw that I was from a previous generation…. My younger ( by eight years) sister… while holding my slide rule…I asked… “how do you use this?”…. And then my even younger sister ( ten years).. asked.. “ what …IS…this thing?”
Amazing lecture, thanks a lot... small remark. the arctan is not the reciprocal of the tangent but the inverse function, the reciprocal would be the cotangent.
I started checking capacitors under load by rearranging the Ic = C(dV/dT) equation to solve for capacitance. In practice it looks like this: Start winding current/ d/dX(Voltage across Capacitor*sin(2*pi*F*0)) = C(you use 0 as time, because the derivative of a sine wave is greatest at 0, and your meter is measuring peak current, so you need to also make the derivative peak as well.) Also a curious connection to help students understand: Capacitors present an impedance equal to Xc with a negative phase angle of 90°. But why 90°? It's for the same reason I stated above. Since Ic = C(dV/dT), the current is proportional to the derivative of the voltage across the capacitor. With a sine wave, the derivative is greatest when the sine function is at 0, this rate of change gradually tapers off,and becomes 0 at the peak. So the derivative of a given sine wave is actually equal to a cosine wave with the same amplitude, frequency, and phase. Cosine waves are shifted 90° This is why current leads voltage when AC is applied to a cap.
I’m just getting into calculus (again) years after graduating and only applying calc to biology, but now I’m applying it to electronics. Reading your comment really got me excited to continue, it’s dusting cobwebs off my mind and got me thinking. Thanks!
@XJ290 Thank you for the kind words! I'm mostly illiterate when it comes to biology, I am an HVAC Service Technician who just happened to get extremely interested in electronics. I've always found it beautiful how many phenomena in this reality follow an exponential pattern. When you apply a DC voltage across a capacitor, it charges in a decaying exponential curve, when you turn on your heating or cooling system, the temperature of the air coming out of the vents will rise or fall exponentially(the change in temperature starts off really high, and gradually eases into a fairly constant value) I've also heard that populations have a tendency to follow this pattern as well. Math is so interesting to me!
Hello sir. I love the video but I have a question. If the capacitor in the dc circuit discharges its voltage in the opposite direction to that of the battery's voltage then doesn't that make the capacitor voltage negative too just as the current? I know that the capacitor voltage just exponentially decays until it reaches zero but it still goes in the opposite direction to the battery voltage. I would appreciate it if you could answer my question thanks.
That is what the switch in the middle is for, when you discharge C, it goes a different route, towards ground in example given. You can/could route that switch to something else or use a diode
Ok so.. ive gone from kind of knowing, to knowing nothing... several times during this. Do i stop or continue? All i want to do is switch this GD mosfet and im mixed up to heck with what resistance after R has raised and lowered v and i at each turn :(
In terms of physics of the circuit this video is next to useless, but in terms of engineering and actually calculating values it's quite useful. I'd love to see a properly calculated capacitance of a spherical air capacitor - please mind that a capacitor has 2 plates not 1, so a proper spherical capacitor is made out of 2 concentric spheres, not one.
Hi bob...something is confusing here, i belive you are refering to a non polar capacitor here.in your video about voltage amplifier (using a microphone as Ac source ) you use a capacitor to block Dc.i guess a polarised capacitor is what you where refering to at that time. Am i correct in my understanding?if not, hence does a non polar also blocks Ac ?
It was 0V across the discharged capacitor (acting like a pice of wire at the beginning), but there was 1V across the resistor - the only one element limiting the current - that's why 1 amp of current. And that's why you shouldn't connect (especially big) capacitor directly to the power source.
Simply brilliant. Thank you Sir.
Best electricity lecure I've ever seen.
Sir. You are the best teacher of electronics on the internet. Thank you!
Crystal clear board work, awesome...
Brilliant lecture Sir
Finally a great explanation after years of kinda knowing
Thank you teacher for this course! Your explanations were clear and well structured
you have no idea how much this has helped me, thanks!!!
I was lost. I looked for Big Bob. I found him. He found me. There for, I was found. Thank you Big Bob
I could always parrot the answers, but now I understand the how. Very cool. Thanks
Spot on, watched this video as a refresher exercise to what I learned in the 70's.
Perfect explanation without bring ODEs into the discussions.I was always struggling a bit with this concept. Thank you heaps!
Very good Bob. A lot of detail crammed into this 36 minutes, very well explained.
Arnold Scwartzenager said “ any rep is a hood rep”…
THIS LECTURE IS…DELICIOUS….
In high school I attended “Vocational Training” / electronics in my junior and senior years… ( 1972-1974)… and resistors, capacitors and inductors… and therefore LRC circuits …and therefore “ right triangles”…. Were…the…. Peak of our mountain tops….
I am interested in reviewing the concepts … just because…. ( and I have some old tube and transistor amps)… I can clean pots, switches and tube sockets all day… but eventually we need to remember how to trace volts … know what to expect …and how to do it safely when sometimes there is 400 volts in the circuit.
Again… GREAT…SERIES…of lectures…
( one of my first benchmarks when I saw that I was from a previous generation…. My younger ( by eight years) sister… while holding my slide rule…I asked… “how do you use this?”…. And then my even younger sister ( ten years).. asked.. “ what …IS…this thing?”
Ooops…”any rep… is a GOOD rep”… this lecture is re- pushing my brain… and it hurts good.
Slide rules and Trig… we didn’t have “useless numbers”… we had “one more step” … and all answers needed to be out to the .oox .. using the slide rule.
Very helpful. Cleared up the confusion I had from my textbooks!
Absolutely Outstanding !! You are a Great Teacher and the Visual Aids Awesome...keep up the great Work
Thank you for giving us an opportunity to understand deeply how the circuit of charge and discharge of a capacity works?.
Amazing lecture, thanks a lot... small remark. the arctan is not the reciprocal of the tangent but the inverse function, the reciprocal would be the cotangent.
Good Explanation sir
Simply great
No words to express
Wow. Simply wow.
I started checking capacitors under load by rearranging the Ic = C(dV/dT) equation to solve for capacitance. In practice it looks like this: Start winding current/ d/dX(Voltage across Capacitor*sin(2*pi*F*0)) = C(you use 0 as time, because the derivative of a sine wave is greatest at 0, and your meter is measuring peak current, so you need to also make the derivative peak as well.)
Also a curious connection to help students understand: Capacitors present an impedance equal to Xc with a negative phase angle of 90°. But why 90°? It's for the same reason I stated above. Since Ic = C(dV/dT), the current is proportional to the derivative of the voltage across the capacitor. With a sine wave, the derivative is greatest when the sine function is at 0, this rate of change gradually tapers off,and becomes 0 at the peak. So the derivative of a given sine wave is actually equal to a cosine wave with the same amplitude, frequency, and phase. Cosine waves are shifted 90° This is why current leads voltage when AC is applied to a cap.
I still can't understand can you make visual video with animation
I’m just getting into calculus (again) years after graduating and only applying calc to biology, but now I’m applying it to electronics. Reading your comment really got me excited to continue, it’s dusting cobwebs off my mind and got me thinking. Thanks!
@XJ290 Thank you for the kind words! I'm mostly illiterate when it comes to biology, I am an HVAC Service Technician who just happened to get extremely interested in electronics. I've always found it beautiful how many phenomena in this reality follow an exponential pattern. When you apply a DC voltage across a capacitor, it charges in a decaying exponential curve, when you turn on your heating or cooling system, the temperature of the air coming out of the vents will rise or fall exponentially(the change in temperature starts off really high, and gradually eases into a fairly constant value) I've also heard that populations have a tendency to follow this pattern as well. Math is so interesting to me!
Outstanding explanation
Is this part of a larger play list? Just want to be sure I'm following concepts in order
Very important info...Thanks, Bob!
Absolutely dream lecture - thank you very much!!
What a wonderful explanation!
thank you so much for this wonderful video.
Very good explanation 🌅🌅
Only explanation that didn't leave me more confused
Fantastic explainer, thanks very much
Incredible video!!
26:07 noted. thanks.
It was wonderful!
How can someone understand and imagine stuff like this. Because of these guys, the knowledge is transferred as it should be between the generations.
Warren Buffett in the alternate universe.
The oracle of Ohm's law
When calculating current@ 19:06, why did you leave out capacitive reactance which I calculate to be 26.5 ohms at 60 HZ?
Sir looks like the Indian actor Navin Nischol... handsome fellow!
Thanks 😊👍🙏💯
@ 19:06, you calculate current as 1.66A based on V and R, but you disregard capacitive reactance. WHY?
really truelly great explanation
Thank you Bob this is the best explanation on yt!
Hello sir. I love the video but I have a question. If the capacitor in the dc circuit discharges its voltage in the opposite direction to that of the battery's voltage then doesn't that make the capacitor voltage negative too just as the current? I know that the capacitor voltage just exponentially decays until it reaches zero but it still goes in the opposite direction to the battery voltage. I would appreciate it if you could answer my question thanks.
That is what the switch in the middle is for, when you discharge C, it goes a different route, towards ground in example given. You can/could route that switch to something else or use a diode
👍🌹
Ok so.. ive gone from kind of knowing, to knowing nothing... several times during this.
Do i stop or continue?
All i want to do is switch this GD mosfet and im mixed up to heck with what resistance after R has raised and lowered v and i at each turn :(
This topic is pretty hard. What about this video do you not understand. I'll try to explain
@@Slovenija_patriot Confused whether more or less resistance raises or lowers current and voltage on the gate.
A snapshot in time.
In terms of physics of the circuit this video is next to useless, but in terms of engineering and actually calculating values it's quite useful.
I'd love to see a properly calculated capacitance of a spherical air capacitor - please mind that a capacitor has 2 plates not 1, so a proper spherical capacitor is made out of 2 concentric spheres, not one.
Current does NOT flow through a capacitor, just in and out of it. He explains this in the beginning.
Hi bob...something is confusing here, i belive you are refering to a non polar capacitor here.in your video about voltage amplifier (using a microphone as Ac source ) you use a capacitor to block Dc.i guess a polarised capacitor is what you where refering to at that time. Am i correct in my understanding?if not, hence does a non polar also blocks Ac ?
By the way great exaplation
How can you have 1 amp of current flow with 0 volts?
It was 0V across the discharged capacitor (acting like a pice of wire at the beginning), but there was 1V across the resistor - the only one element limiting the current - that's why 1 amp of current. And that's why you shouldn't connect (especially big) capacitor directly to the power source.