WEBVTT 00:00.270 --> 00:01.680 Hello and welcome. 00:02.080 --> 00:07.650 So before jumping into console and just running through the simulation, let's go back and learn a little 00:07.650 --> 00:08.550 bit of theory. 00:08.760 --> 00:12.060 What is actually at the charging of a capacitor? 00:12.240 --> 00:12.810 Don't worry. 00:12.810 --> 00:18.210 I will not take too much time to explaining all the basics, but I'll just go through the very basics 00:18.210 --> 00:25.740 which is needed so we know that a capacitor is present or something like this where let's say when the 00:25.740 --> 00:33.090 capacitor is charged, one side will be positively charged, something like this, and the other side 00:33.270 --> 00:36.810 for a battery powered capacitor will be negative. 00:36.810 --> 00:43.780 So positive and negative, which will form a potential gap and then the energy stored in this fashion. 00:43.830 --> 00:47.250 This is how the capacitor actually stored charge. 00:47.640 --> 00:54.200 So for, you know, starting the charging up a capacitor, let us consider a very basic circuit. 00:54.870 --> 00:59.670 So we have our battery and then we have a resistance connect to it. 00:59.940 --> 01:06.690 Let's say we have a switch and then we have a capacitor and our circuit is closed. 01:07.380 --> 01:09.420 So we have to here. 01:10.680 --> 01:18.180 This is our this is capacitor C, so when the circuit will be closed, the potential across the receiver 01:18.180 --> 01:23.340 will be we are and the potential across the capacitor will be v.c. 01:24.300 --> 01:30.720 So when a battery is connected to a series Destra and Capacitor, the initial current is high as the 01:30.750 --> 01:35.790 battery transport charge from one plate of the capacitor to the other. 01:35.790 --> 01:42.420 The charging current asymptomatically approaches zero as the capacitor and becomes charged up to the 01:42.420 --> 01:43.230 battery voltage. 01:43.590 --> 01:50.670 Charging the capacitor restores energy in the electric field between the capacitor blades and the rate 01:50.670 --> 01:52.690 of charging typically describe the term. 01:52.980 --> 01:55.350 Uh, that is the time constraint so far. 01:55.350 --> 02:03.420 This circuit, the time constant is our C, so this term is important for charging of a capacitor. 02:03.870 --> 02:07.980 Now let us, uh, just write it down in very basic form. 02:08.250 --> 02:10.110 So VB will be. 02:10.110 --> 02:11.960 We are plus v.c. 02:11.970 --> 02:17.910 This is very clear, the potential difference, uh, across the register and the potential difference 02:17.910 --> 02:19.110 across the capacitor. 02:19.440 --> 02:28.200 So which can be simplified as I r that is current time resistance plus Q by C that is the charge by 02:28.200 --> 02:30.300 the capacitance which is the voltage. 02:30.390 --> 02:30.650 Right. 02:31.980 --> 02:40.920 So if you see at time DeCola Desierto, that is when the circuit is open, uh, so the charge will be 02:40.920 --> 02:49.920 zero, the potential across the capacitor will be zero and the current will be Vehbi by R right. 02:49.920 --> 02:51.940 Initially when it is just starting. 02:52.440 --> 03:01.860 So at the very last time let's say DeCota T1, which is very large timelessly infinity, then the charge 03:01.860 --> 03:09.120 will be three times will be right, because at very last time the charge will fail up until it gets 03:09.120 --> 03:16.800 to equal to the potential difference across the source and v.c will tends to be it will be slightly 03:16.800 --> 03:25.770 less than VB, but still close to Fibi and the current flow will be zero Y because the current will 03:25.770 --> 03:28.240 flow until the capacitor is fully charged. 03:28.350 --> 03:28.710 Right. 03:28.890 --> 03:32.760 So as soon as the capacitor filters, the current flow will be zero. 03:33.330 --> 03:36.750 So now let's try to look at how the plot actually looks. 03:36.750 --> 03:37.890 So let's do a thing. 03:38.280 --> 03:40.430 Let's draw the curve. 03:40.800 --> 03:46.230 So I'll draw this part with black and then the other part with pink. 03:48.160 --> 03:58.570 And what we will do this is the charging current and this is the charge on capacitor. 04:01.020 --> 04:04.560 OK, and let's say this is the time. 04:06.040 --> 04:16.000 This is the time this is the to zero now, as soon as you turn on the switch in the circuit, so as 04:16.000 --> 04:22.410 soon as it's turned on the switch in the circuit, what will happen is the current will start from a 04:22.430 --> 04:28.080 maximum value and then it will slowly die down and saturate to zero. 04:29.230 --> 04:36.850 And similarly, the charge in the capacitor will increase and it will saturate to value. 04:37.330 --> 04:41.230 This saturation value is three times Vehbi, right? 04:41.470 --> 04:43.080 We already discussed this here. 04:43.330 --> 04:52.780 So the saturation charge will be three times the VB and the initial current this is the I-Max, which 04:52.780 --> 04:57.130 is at the starting phase will be Vehbi by R. 04:57.580 --> 05:00.790 So this is V, B by R, right. 05:01.030 --> 05:03.630 This is one very basic theory in physics. 05:03.970 --> 05:12.820 So what we will do is let's jump back to commercial in our next lecture and then we'll try to set up 05:12.820 --> 05:17.160 the circuit and then we'll verify all these theories together. 05:17.290 --> 05:17.640 Right. 05:17.980 --> 05:22.480 So thanks for watching and we'll be back in our next lecture.