Electronic Basics #14: Capacitors

Electronic Basics #14: Capacitors


If you ever had the problem that your monitor or TV just stops working at some points Then there’s a big chance that you can repair it by replacing the dodgy capacitors on the circuit board and when you think [about] it almost every circuit of consumer electronics Has such capacitors in one form or another? so in this video Let’s talk about what a capacitor is what the ratings on it means and what functions he fulfils in our circuits? Let’s get started In order to understand some fundaments of capacitors it would be the best to build one ourselves I used this aluminum sheet and made one line in the middle of the material and another line at 1/3 of the length of the other side Then I used my saw to cut out my four pieces and use my clamps to position the two smaller [ones] Parallel to each other with a very small distance and that is basically a capacitor even the wiring symbol looks like this if I hook it up to a 30 volt power source by connecting plus to one sides and Minus to the other we can see that just for a fraction of a second a very small amount of current [is] flowing This currents AKa Electron flow charged up the plates by creating an electron [excess] on the negative side and Thus an electrostatic field is created between the plates Which stores our electric energy if we measure the capacitance? We see that it is around 50 [to] 60 picofarads That is nothing and in my [case] the capacitor cannot even hold a charge when I disconnected from the power source Normally they do this and can supply the stored energy from the electrostatic field just like a battery can supply power just way way less power the more capacitance and Maximum voltage rating it cuts the more power it can deliver now back to our plate capacitor We can actually improve the capacitance by increasing the surface of the plates This way there are small space for electrons and thus a bigger Electrostatic Fields and if we get the plates even closer to each [other] [without] touching them we can also increase the capacitance Since the Force on the electrons to the positive plate Increases and the stairs again more space for other electrons, but we are still only at 110 picofarads with the big plates to improve this even farther we can also add a dielectric material Like distilled water in the middle of the plates the H2O Dipoles line with the electrodes static fields and increase the force on the electrons which again creates more space for others I? Was even capable of creating a 2.5 micro farad capacitance like this which is not bad? This is basically how all capacitors work in one way [or] another if we take apart a real-life example like this electrolytic capacitor we can see it also just contains of metal films with a dielectric material in the middle and Since the Metal is very close to each other and the dielectric material is certainly not a perfect isolator There’s always a voltage limit given Everything above has the potential to create a spark over and thus destroying your capacitor And it’s also important to not reverse the polarity of the electrolytic ones. They surely don’t like that as well let’s move on to how they behave in DC and Ac Circuits and for this you might want to watch my inductor coils video before hands since there are many Relations between those two first of all let’s take a look at switching operations this time the voltage of a capacitor cannot change instantly Because it needs to build up its electrostatic fields or turn it into another kind of energy But the current will change immediately and will slowly decrease while the capacitor reaches its maximum voltage This is used to keep voltages at a stable level at the output of your power supply Or to decouple and IC in your [circuit] We can also use them in Combination with a resistor to charge them up in a specific time this way they can be used to create different signals like a square wave with this [five] Pi 5 timer if we move over to Ac signals with the sine wave We can also find out that a capacitor. Just like a coil creates another form of resistance Called Capacitive reactance But in contrast two coils the capacitance and frequency is in direct proportional to the [value] of reactance that means if I decrease the capacitor Less current will flow and this way our led will not light [up] very much anymore And if I decrease the frequency, it’s the same less current will flow the final formula for the capacitive reactance [looks] like this since we know that this is basically a frequency based resistor we can easily build our C filters which keep certain low frequencies out or certain high frequencies out and there is no big difference between Rl and RC filters you usually use our sieve because Capacitors are mostly cheaper and small in comparison to coils Lastly let’s hook up our microwave motor to our power line And we see that it still creates a phase shift up around 36 degrees as I told you before This creates reactive power which strains our power grid in order to get rid of this we can add a capacitor in Parallel Which also creates a phase shift but in the other direction? This compensates our inductive load and relieves the power grid from the reactive power and with that being said You already know quite a lot about capacitors. I hope you like this video. If so don’t forget to [like] share and subscribe That would be awesome Consider supporting me through my patreon campaign to keep such videos coming stay creative And I will see you next time

100 comments / Add your comment below

  1. I understand a little bit except why people put so many capacitors on a mother board
    I don't know what that does

  2. I had never thought of tearing down an electrolyte capacitor, that was very interesting to watch!

  3. Indirectly proportional … unlike German … English forms adverbs from adjectives by adding "-ly" (in many cases).

  4. Its good for me .I like it because i prefer the electronic work

    can you do a favor for me

    plz give me a video about HOW TO USE MULTIMETER plz plz

  5. I got a 5 (max 5) on the advanced placement test for calculus based electricity and magnetism, but I still don't know how to use a capacitor in a circuit…

  6. nice video, sir tell me, what r the selection parameters for capr means I am going to fix in ckt, how many parametes I should consider. ex. 50uf is found in ckt, then why 50uf is used, why not 100uf, .. plz reply..

  7. cool video thank you very much. electron flow however is disproven or atleast inaccurate. https://www.youtube.com/watch?v=JQnSz_e7jvc lets let this guy come to life now

  8. I am soo happy that I found this channel (I am 14 years old from Slovenia and I am so interested for ELECTRONICS and in class I am genius) !!!

  9. For those who would like a tiny analogy:
    The absolute best analogy for capacitors and resistors is a mass-spring system. Voltage would be force, velocity is current, inductor is Mass, capacitor is a spring, and resistance is friction.
    https://instruct.math.lsa.umich.edu/lecturedemos/ma216/docs/3_4/spring.png

    Trust me the equations are Identical to a rlc circuit.

  10. When explaining charges, you should probably explain with electron flow (negative to positive), not conventional current (positive to negative). Makes more sense.

  11. My issue is a little off topic we build custom motorcycles and the bigger the motor the motor starin that is put on the batteries even if high CCAs. So what we are thinking about doing is adding a capacitor to give the battery a boost during starting. I have been watch all sorts of youtube videos on this and people are using anyware from 14v-50v capacitors. From my understanding is the voltage doesn't matter since that is just a maximum voltage the unit can handle and with heat and age that maximum voltage rating can drop causing the capacitor to burn out. So we are planning to use a capacitor at least 3x the bikes voltage which is about 13.8. But what we are most concerned about is the farad rating. I watch an HVAC companies video on capacitors and they say that too large of one can burn out their motors so they deal with microfarads instead. So we are wondering if this will be an issue with a motorcycle starter and other electronics that there is a certain farad rating we should stay below or not? I have see all sorts of capacitors for cars that ranged from 1 to 50 farads and more. I don't think we need anything that massive but we want something to give a good boost to the battery at start up so the bikes fire easier instead of lagging on the compression stroke with all the lights fading looking like the battery might not have enough oomf. Can you advise a capacitor rating? Since they will need to be small enough to hide on a motorcycle we will most likely just have to order basic capacitors from overseas and what not to wire ourselves compared to one of the large stereo units that comes complete ready to bolt in and connect the wires. Any help would be appreciated. Thanks,

  12. You load lot of information, and virtually hands on experience in short videos. Keep on making videos. Eventually, I shall go through all of them.

  13. Can you help me?
    About the capacitor and inductor?
    https://www.youtube.com/watch?v=AwUDncGaDKg
    Thank you so Much!

  14. you have a funny pronounciation 😀 'th' -> 'f', 'voltage' -> 'vultage' , 'all' -> 'oll' 😀 but the explaination is good do far 🙂

  15. got a huge tv, broken of course from my father, took it apart, replaced 1 capacitor.. and now i have a huge tv!, a huge improvement from my b/w crt tv, i always tell this story, but this time i at least have the context of this video to go with it.
    never throw something in the trash without attempting to repair it!

  16. This may be a vague question, but… Do you know what would be the average capacitance for a polarized capacitor, that can hold 20 kilovolts? Or if there is a method to finding the normal capacitance to keep something going for about 2 seconds?

  17. Can someone please explain, how to calculate required capacitance for a particular circuit or capacitance for a led/motor? how to calculate the value required?

  18. Hey, @GreatScott, I know a very interesting trick with eletrolitic capacitors you could use for many projects…maybe you already knows the trick..maybe not…Well, the trick allows you to REVERT the capacitor's POLARITY without destroying it. To do that you simply need to solder two capacitors in series where the soldered pins are the same polarity and voilah (I think the word is voilah) you can revert the polarity without problem and charge normaly the capacitors. As everybody knows, in this configuration we sum the voltages limits of both capacitors and apply the formula for the total capacitance 1/Ceq = 1/C1 + 1/C2 + … + 1/Cn …hope you enjoy the trick and let me know if you tried! Greetings from Brazil! =)

  19. What type of capacitor would you recommend to put in front of a thermal flasher on a car to make it blink faster

  20. Great explainatio n.

    After I removed capacitor from circuit board. How do I know which leg is positive, which is negative?

    Your video demonstrate connect legs in wrong direction will cause capacitor to explore.

  21. May I ask below DIY capacitor geometry questions?

    Bigger the roll (bigger diameter) make higher capacitance.

    More surface contact to + and – leg make higher Amp capacitor.

    Does longer the cylinder roll make higher DC voltage?

  22. I made my own capacitor from 2 sheets of aluminimium foil separated by cling wrap. I folded it all up into a cube and taped it. I actually got 500nf out of it. But it leaked all of its charge very quickly. Rimstar has videos on making caps, dry andelectrolytic. I should make one of those some time.

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