 Hello everybody, this is Jyotana. Today we are going to practically see the impulse response of an RC circuit. So, here we have an RC circuit. It consists of a resistance of one kilo ohms and a capacitance of one microfarad. These two probes provide the input to the RC circuit and through these two wires we fetch the output out on the oscilloscope. As an input, we give impulses at regular intervals to the RC circuit. You can see this sharp narrow pulses here on your screen. We know that the impulse response of an RC circuit is an exponentially decaying function. Since we have given impulse as an input to the RC circuit, on the oscilloscope we observe that the output is indeed an exponentially decaying function. Showing that if any system is given impulse as an input, then the output is the system's impulse response. Talking about impulses, not only electrical systems, but in everyday life, like things happening around us, we observe impulse and their impulse responses. Let us take up some of those examples. So, as Jyotana has mentioned, there are a lot of real-life examples of impulses. I am Meghesham. I am going to talk about some of these real-life examples now. So, you have seen a nail and a hammer. So, you have a nail and you have a hammer. So, when you hammer the nail as such, the contact of the nail and the hammer is just for a few milliseconds. But the momentum or the force that you impact in that few seconds is really large. So, you can consider this as an impulse being given to the nail. And you have seen in most of these movies, the guy gets a heart attack and then they do a defibrillator and then they kickstart the heart. So, let me just talk about this one. You have a battery here. You have a battery and you have two switches which will connect the battery to a capacitor. There is an inductor and there is one more switch. And then here you have the patient's heart. So, what you do in a defibrillator is, you have the battery, then you charge the capacitor and then you open the switches. Now, it is totally charged. Now, it is charged. So, the guy is holding the defibrillator. As soon as he presses it across the heart and then jump starts the heart. So, what it does is, you close the switch. It completes a circuit between the capacitor and the heart and all the energy across this given to the heart as an impulse. So, basically that is why you call it kickstarting the heart. And let us get to one more example. The other example should be, you have, you, most of you might have seen your parents or you know, you yourself might be having cars. So, when you switch on the car with a key. So, the engine, how it starts is basically a small spark comes when you switch on the key. And this spark starts the engine and then it is similar with tube lights. So, you have, if you have a tube light with a spark plug. So, what it does is, it gives a small spark to start the tube light. That is also can be considered as an impulse. And let us talk about momentum change now. Suppose, a guy is travelling in a car and he is travelling real fast. Suppose, a guy is travelling in a car and he is travelling real fast. And then, I do not know, maybe he did not watch it, but he meets a brick wall. And then, you know, the car just comes to a stop. I mean, it is damaged, but say the car has a mass m and it is moving at a velocity v. And then it, as soon as it hits the brick wall, it comes to a stop. As soon, say the car has a mass m and it is moving with a velocity v. And then, as soon as the car, so let us say the car has a mass m and the velocity v. It is moving and then it hits a brick wall. So, the car crashes, but it, you know, it goes from velocity v to 0. After it crashes, it is 0, obviously, in a few milliseconds. So, the momentum which was first m v, it is now 0. So, if the car is moving really fast, say at, say, 60 miles per hour. And you know, cars weigh, you know, 2 tons or something like that, which is 2000 kilos. So, the momentum change, the change of momentum from its moving, let us say, assume it is moving at a constant speed, the momentum change from this to 0. And this time here is very, very less, milliseconds, you know, less than that, because you just hit a brick wall. Now, if you look at the change of momentum, this would be an impulse. Momentum just went from being so high to 0. How many of you have, you know, just got a shock, like, or, you know, touched a burning pan? Then you just retrieve your hand back, because the neurons, they actually send electrical impulse to the brain, saying, oh, I touched something back. So, just get back. Or, you know, when somebody tries to hit you, you will, like, close your face altogether, because it is kind of an, you get all these impulses in everyday life. Your body is basically made up of electrical impulses. So, this signals the body sends you the touch, the tap. These are all electrical impulses. So, your body is made up of electrical impulses. Impulses practically make a lot of sense, but I need to mention this thing. An ideal impulse will not exist practically, because an ideal impulse is infinity at a single point. So, practically we say impulse is something, you know, a signal which has high amount of energy, or, you know, not high amount of energy, a signal which has high value in a very less amount of time. And impulses can be in many domains. Now, you have seen impulses in time. How does an impulse in frequency look like? You will get to know more about this when we talk about Fourier transform, because a pure sinusoid is an impulse in frequency domain. So, you know, when you talk about impulse, ask in which domain? Because a spark plug, it is an impulse as an input. But how? Is it impulse in time? Is it impulse in, you know, heat? So, an impulse is basically a signal which is really high in a really small range of the base unit we are considering. The base unit can be time, frequency, I mean, whatever. So, I have given you some examples of impulses which occur in practical life. And impulses are there everywhere. You just have to notice them. I would like to see you guys discussing on the forums on what can be impulses and what cannot be impulses. And thank you very much.