Having defined the impulse (delta) function and equipped with convolution we are ready to make headway in the time domain. But first we need the impulse response. In this chapter we start by generating the impulse response using a limiting process. Specifically we figure the response (here of a parallel RC network) due to a regular pulse. Then we observe this response as we make the pulse width smaller and height larger; in the process we observe a definite trend. Next we formally derive the impulse response analytically. Then we practice more on a couple more circuits, including high-pass and low-pass voltage filters. In all of the tried cases the impulse response dies off at large time, though that is not the rule (for example, circuits with high Q will oscillate forever). Notice the whole while we are still in the time domain; in the later chapter we will figure the impulse response working in the frequency domain, by simply finding the inverse transform of the transfer function. The premise again is that if we know the impulse response we can know any response using convolution as will be shown in the next chapter.