what is the difference bertween analog and digital?

An analog signal is any continuous signal for which the time varying feature(variable) of the signal is a representation of some other time varying quantity. An digital signal is that takes on only two values, off or on, typically represented by "0" or "1".Digital signals require less power but more bandwidth than analog and copies of digital signals can be made exactly like the original. Above is basic definition of the two but a you said you wanna top and all so i would suggest you to watch below video on youtube to understand better and score well Good luck. http://www.youtube.com/watch?v=M_nTmRtAD98&feature=related http://www.youtube.com/watch?v=1go6ITQXSlQ

analog signal is a continuous time signal,signal will be continuous in nature,is independent variable of time.analog signal is an uncountable set of signal. discrete signal is discrete time signal,signal will not be in continuous in nature,varies with respect to time.discrete signal is a countable set of signal. have a nice day :)