At any given moment, every terminal is in one of the two binary conditions low (0) or high (1), represented by different voltage levels.

 

In most logic gates, the low state is approximately zero volts (0 V), while the high state is approximately five volts positive (+5 V).

 

 

There are seven basic logic gates:

AND, OR, XOR, NOT, NAND, NOR, and XNOR.

 

 

Logic states
True	False
1	0
High	Low
+Vs	0V
On	Off

Once the Boolean expression for a circuit output has been obtained, the output logic level can be determined for any set of input levels