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

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