Digital Logic-Think Binary !

Think Binary!

Let's examine a typical situation. You have some sort of device that generates a logic signal.
It could be a telephone that converts your voice signal into a sequence of zeros and ones.
It could be the thermostat on the wall that generates a 1 when the temperature is too low, and a 0 when the temperature is above the set point temperature.

The logic signal, A, takes on values of 0 (FALSE, OFF) or 1 (TRUE, ON). That signal might really be a voltage, a switch closure, etc. However, we want to think in terms of zeros and ones, not in terms of the values of the voltage.






Operations on Logic Signals

Once we have the concept of a logic signal we can talk about operations that can be performed on logic signals. Begin by assuming we have two logic signals, A and B. Then assume that those two signals form an input set to some circuit that takes two logic signals as inputs, and has an output that is also a logic signal. That situation is represented below.







The output, C, depends upon the inputs, A and B. There are many different ways that C could depend upon A and B. The output, C, is a function, - a logic function - of the inputs, A and B. IWe will examine a few basic logic functions - AND, OR and NOT functions and start learning the circuitry that you use to implement those functions.