RC Circuits (3 of 8) Charging & Discharging a Capacitor, An Explanation

[@MrBrandvold]

My very "special" AP2 students, love your explanations! :):

[@stepbystepscience]

Great, tell them thank you from me and thanks for letting me know

[@funmastiandlearn2885]

@@stepbystepscience why my current vs time graph is positive in discharging of capacitor??

[@stever3886]

This video should be required before going into a circuits lab. Love the little simulator. My son is taking circuits this semester and I will forward this to him. Thanks for the really great beginner video.

[@stepbystepscience]

Glad it was helpful and thanks very much for your comment!

[@jobayerrifad544]

you just saved my life. i was struggling to understand all these charging and discharging phases.your videoes helped me a lot.Thanks a ton (Y)

[@stepbystepscience]

Excellent thanks for letting me know...I spent a lot of time trying to figure out the best way to put that video together. Glad that you found it helpful. You can see a listing of all my videos at my website, www.stepbystepscience.com

[@divyeshjoshi7581]

finally understood what charging and discharging means, I am in 2nd semester Information Engineering program and because of this topic I almost felt like I should quit because I am too dumb to study electrical engineering. Thank you so much. I will tell my all friends and classmates to subscribe to your channel :)

[@stepbystepscience]

I am very happy that you found the videos to be so helpful. Don't give up. And thanks for telling all of your friends to subscribe.

[@cardinality1975]

This is how I felt in my circuits class when we hit RC and RLC circuits as well haha, it's a learning curve but I believe in both of us!

[@rabiamehmood3507]

This is such an amazing video! It explained the whole RC circuit so clearly! Thank you so much!

[@stepbystepscience]

Thank you very much for your comment, I spent a fair amount of time putting these videos together.

[@rabiamehmood3507]

Step-by-Step Science It definitely shows. I really appreciate it. I am actually studying for a final in less than 24 hours and did not understand when an RC circuit is charged vs uncharged based on the switches alone but now I understand it is much more complicated than a simple open switch = charging definition. The brevity didn't compromise the information either. What a perfect combination!

[@stepbystepscience]

I wish you much success on the final.

[@BamideleSalaudeen-qf5qj]

physics lab exams tomorrow....lucky to have found this channel tbh

[@stepbystepscience]

Best of luck and thanks for watching

[@onefixitman]

I guess you see a lot more Velocity problems than Voltage problems. You say Velocity once in a while for V. I always see E or V as Voltage mostly because I was a Nuclear Electrical Operator in the Navy. I watch these videos to study for entrance exams. Even though I learned these formulas 30 years ago I still need to study them over time for interviews and entrance exams to keep fresh in my mind. All the young folks studying these formulas need a practical reason to remember this stuff and that reason is to do well on entrance exams prior to your interview for an amazing opportunity. Cheers and Bravo Zulu.

[@stepbystepscience]

thanks for the comment

[@qaisar.sulaiman]

This genuinely saved my life... wow

[@stepbystepscience]

Glad to hear it!

[@adnanamer2]

Very nicely explained specially that simulation in this video helped me understand many things. Hope you continue coming up with more videos on these topics keep it up.

[@stepbystepscience]

Thanks for the comment, it took me a while to put the whole thing together.

[@allegra1045]

if i pass my physics exam it will be all thanks to you

[@stepbystepscience]

Good luck, you can do this!

[@AbdulAzizAlDhyaie]

What a fantastic explanation! You really awesome, you saved my educational life. Wish you all success in your life

[@a-baby9]

habibi allah khalik

[@pedrosanga391]

Great play list. Thank you very much.

[@stepbystepscience]

You are very welcome.

[@VIPULSAINI1]

Thank you very much sir big salute from here ( India)

[@stepbystepscience]

Once again, thanks for all of your comments.

[@DanielGarcia-ur9tx]

What would the current look like if you add another capacitor in series? In parallel?

[@Charleslima33]

Thank you for the explanation, great tool, easy undertanding, keep up the good work !

[@Gigifulcrum]

Thank you, thank you, thank you! You helped me out tremendously.

[@stepbystepscience]

The pleasure is all mine, thanks for letting me know. You can see a listing of all my videos at www.stepbystepscience.com

[@niloofarsaghafi7067]

very helpful video, thanks. But I really wanted to see the changes IF we let both switches on at the same time. Unfortunately you didn't show that. Except that the video was awesome.

[@stepbystepscience]

Glad it helped, thanks for the comment.

[@ronricogarcia3216]

Very well explained! Thanks.

[@stepbystepscience]

You're welcome! Glad you liked it.

[@cyrus9893]

excellent video in RC circuit. Thanks a lot

[@stepbystepscience]

Thanks for taking the time to comment

[@TheMoviesfable]

Why current while discharging is negative? Capacitor has the same polarity as source which it was charged by, I can't figure out why would it be negative, as current flows in same direction as it would from source.

[@stepbystepscience]

Because the current flows back in the opposite direction when the capacitor is discharged.

[@mohammadvahidi5483]

why the current during discharging was negative? love your videos tnx.

[@stepbystepscience]

Because it is flowing in the other direction.

[@BinhNguyen-sf5tq]

Excellent explanation on RC circuit . Thanks a lot

[@johnx9318]

That was very informative. Thanks.

[@stepbystepscience]

You are very welcome.

[@johnlee7377]

i really needed this video, thank you

[@mrsemifixit]

In the first example, why does the current graph for the lightbulb show negative 2 amps and not positive like the voltage?

[@Journeytoliberation1998]

great explanation sir.. hats off to you

[@stepbystepscience]

Thanks you for the comment.

[@abelashenafi6291]

these is the best video i've seen so far on RC circuits. these videos are really helpful. I was wondering how to do simulation on the PHET website but i couldn't when ever i click on the play sign, it download a .jnlp file and i could find an application that could open these kind of files. please help what kind of software could i use to run simmulations on a windows 10 operating system?

[@stepbystepscience]

I think it is Java.

[@psureshmanikandan]

This video was soo helpful, but I have a doubt on the discharging part, the Vc and Qc while discharging will decrease but will it reach zero????, because at some point the stable condition will be established and some potential and charge will be there at the capacitor ryt

[@stepbystepscience]

The capacitor discharges to 0 volts.

[@meetpatel8197]

First of all thanks for making this video, but i m confused why there is negative 2 voltage peak across resistor which is connected blumb ? Does the direction of current matter how to predict that?

[@emankhatib4484]

REALLY helped! thank U

[@lokmack3746]

Very good. Is it any different when it is in series?

[@stepbystepscience]

Yes, of course.

[@lokmack3746]

@@stepbystepscience could you please explain the difference?

[@christoffere425]

When t = 0, does this mean that the switch is open? And when switch is closed t = 1 (or more)? Is this always the case? That the switch is always closed on any circuit when t = 0?

[@Vukuzenzele]

Good video. What would happen if both switches were closed simultaneously?

[@stepbystepscience]

Current will flow through the bulb and continue flowing through the bulb. Current will also flow to the capacitor until it is fully charge and then no more current will flow through that branch, but current will continue to flow through the bulb. Does that answer your question? You can see a listing of all my videos at my website, www.stepbystepscience.com

[@Vukuzenzele]

Step-by-Step Science Yes thank you, would the bulb flicker because of the constant discharge of the capacitor?

[@stepbystepscience]

The bulb would not flicker and the capacitor does not constantly discharge. In this circuit the capacitor would charge and then stay charged.

[@janaalkandari3311]

very clear and helpful thank you!

[@ally_270]

When i do not have a battery in the circut, and the capacitor is fully charged. once i close the switch, the capacitor will discharge but the current will start charging yes? Cause if the capacitor is fully charged then no current will be flowing in the circuit, but now that the capacitor is discharging, current will start flowing and “charging” across the circut. Please correct me if i am wrong

[@stepbystepscience]

Sounds correct, but I believe you are using the term "charging" incorrectly. The current does not charge across the circuit. When the switch is closed the current start flowing through the circuit.

[@congkhanh2310]

at 9:13 I think the current is not maximum value because at that time, capacitor current is equal to C times dv/dt and equal to zero since Voltage across capacitor is in steady state (V=const)

[@funmastiandlearn2885]

Why my current vs time graph is positive in discharging of capacitor???

[@stepbystepscience]

switch the leads of the current meter and it will become negative. Often we are most interested in the magnitude of the current or voltage.

[@willgoss788]

The calculation of Charge across the capacitors needs to be commented that Total Capacitance is 4 microFarads not 4 microCoulombs as shown on the analysis, which ultimately leads to the correct answer.

[@Osmanity]

all hero´s dont wear cape

[@stepbystepscience]

I have a pencil and a calculator!

[@Osmanity]

@@stepbystepscience xDDDD

[@user-rg3mb1wy1r]

Love it!

[@17joren]

Thanks for these comprehensive videos, very helpful! One question though: Why was the current across the bulb negative in the sim graph? Isn’t the charged capacitor acting like a battery to the bulb, so current flows normally when it discharges? If the blue dots are electrons, they were moving the same direction as when you first charged the cap in first phase…

[@imagination7710]

Nice vid man

[@shutnawi6635]

thank you

[@stepbystepscience]

Welcome!

[@sridharchitta7321]

Why should a capacitor discharge? Imagine the capacitor with all its charges is kept inside a bag and tied at two open ends (open-circuit). The positive charges on one plate are attracted strongly to the electrons on the other plate, and the electric field is strong and uniform between the opposite charges on the plates. The opposite charges on either plate seem to hold each other tightly. The field is not so strong to cause the electrons to cross the gap and reunite with the positive charges. There is a fringe field at both ends ready to burst the bag, but the open circuit does not allow charge flow in the external circuit. The electric fields of surface charges which move onto the wires from both the plates and the fringe field will, during the initial transient when the wires are attached to the plates, combine to make the resultant electric field in the wires, zero. The fringe field is different from the field between the capacitor plates. When the charged capacitor is short-circuited using a wire, the effect is to open the tied ends of the bag and the charges are released. The fringe field causes the initial crucial release of charges for further flow of the charges….and development of surface charges that will enable the charges to flow around the wire, and neutralize each other. After all the charges on the plates are neutralized, the circuit attains a state of static equilibrium, a natural relaxed state of equilibrium and we say the capacitor is discharged. Electrostatics and circuits belong to one science not two. To learn how a capacitor charges and discharges and the origin and role of the fringe field in the circuit process it is instructive to understand Current, the conduction process and Voltage at the fundamental level as in the following two videos: i. kzbin.info/www/bejne/iHbWiJeabJukrsU and ii. kzbin.info/www/bejne/bnO0fpKurJeFnNE It is not possible in this post to discuss in more detail the formation of the fringe field when a capacitor is charged and discharged. The last frame References in video #1 lists textbooks 3 and 4 which discuss these topics in more detail using a unified approach and provide an intuitive understanding of discharging a capacitor with the help of sequential diagrams.

[@rameshwarshelke4633]

Thank you 😊 sir

[@stepbystepscience]

Most welcome

[@JustNow42]

Just some remarks: the energy in the charged capacitor is C V^2 , the lost energy in the charging resister is 1/2 C V^2 surprising this is not a function of the resistance ,

[@joparkcat]

nice vids

[@stepbystepscience]

Thanks very much!

[@terrytan4330]

nicely presented

[@stepbystepscience]

Thank you very much, took a while to put it all together.

[@parfittelcano8818]

For the graph of I when the capacitor is discharging, why is it going down still? When it was charging it was already going down to 0. When discharging, shouldn't it be going up?

[@stepbystepscience]

A it hard to explain here, but the charge decreases until the capacitor is fully charged and then goes back to zero when it is discharging.

[@tomasgonzales]

This simulation is using non conventional (real) current flow right?

[@stepbystepscience]

electron flow. You can see a listing of al my videos at www.stepbystepscience.com

[@abhishekanand2k4]

Kindly close the both switch..... We want to see electron behaviour in out from capacitor....

[@oliverg6875]

much better than my prof my prof really sucks

[@stepbystepscience]

Sorry, but thanks for watching and commenting.

[@annadkeelenius6217]

thank you Soooo much !

[@stepbystepscience]

You are very welcome, thanks for watching and commenting.

[@batmanking541]

so good!

[@frogprincey]

@6:59, i think you mean capacitor is fully "discharged"

[@stepbystepscience]

Kann sein.

[@Luxcium]

Nice video tanks a lot

[@soksahas8952]

Save my life !

[@stepbystepscience]

Awesome, thanks for commenting

[@machobutter2478]

LOVE YOU

[@jz2710]

Thanks

[@stepbystepscience]

You are welcome.

[@jeffryblackmon4846]

I think the simulator confuses more that it explains. 🤔

[@stepbystepscience]

Sorry.

[@nilenjarackal7013]

Hey! anyone here on comments..can u pls tell me where i can get the picture of this circuit in 0:07..pls..let me know

[@stepbystepscience]

What do you mean a picture of the circuit? Take a screen shot of it or do you need something else. Please, let me know and I can send it to you.

[@nilenjarackal7013]

Sir,I can't take the screenshot cause that diagram has things written on it..where did u get that diagram sir.. I need it for my project

[@stepbystepscience]

@@nilenjarackal7013I made it.

[@nilenjarackal7013]

Step-by-Step Science oh ok sir

[@stepbystepscience]

@@nilenjarackal7013I need your email or something like that

[@iliashishoski1261]

nice!

[@hochunchan5603]

The capacitor has been removed...

[@user-dw7lf5xr8k]

그림좀 잘그려라

[@stepbystepscience]

Draw a little picture of what?

[@ahmetkarakartal9563]

thank you

[@stepbystepscience]

You're welcome