Introduction Logic states True False 1 0 High Low +Vs 0V On Off Logic gates process signals which represent true or false . Normally the positive supply voltage +Vs represents true and 0V represents false. Other terms which are used for the true and false states are shown in the table on the right. It is best to be familiar with them all. Gates are identified by their function: NOT, AND, NAND, OR, NOR, EX-OR and EX-NOR. Capital letters are normally used to make it clear that the term refers to a logic gate. Note that logic gates are not always required because simple logic functions can be performed with switches or diodes: Switches in series (AND function) Switches in parallel (OR function) Combining IC outputs with diodes (OR function) Logic gate symbols There are two series of symbols for logic gates: The traditional symbols have distinctive shapes making them easy to recognise so...