A·B + C — logic gate diagram

intro2 primitive gates, 2 levels

Answer

2 gates, 3 inputs; output column 01010111

Why this example is worth doing

The minimal two-level AND-OR network, and the diagram every other one on the page is a variation of. One AND gate takes A and B, one OR gate takes that output and C. The page uses it to establish the drawing conventions the rest of the site inherits: inputs enter on the left in declared order, signal flow is strictly left to right, and gate depth maps to a column so that propagation delay is readable as horizontal distance. It also introduces the IEEE/IEC toggle without the diagram reflowing.

Try your own input in the Logic gate diagram builder. Draw an expression as a gate schematic in IEEE or IEC symbols and copy it as an image.

How the answer is reached

Netlist

Netlist — columns Node, Gate, Inputs
NodeGateInputs
g0andi0, i1
g1org0, i2

Truth table

Truth table — columns #, A, B, C, F
#ABCF
00000
10011
20100
30111
41000
51011
61101
71111

Compare with

Open this example in the Logic gate diagram builder

The field arrives filled in with this example’s input.

Note:

Notation this page assumes

  • Symbols: · is AND, + is OR, ⊕ is XOR, a prime or an overline is NOT. The field also takes ∧ ∨ ¬ ~ ! & | and the words.
  • Operator precedence, tightest first: NOT, then AND (including juxtaposition), then XOR/XNOR, then NAND/NOR, then OR, then IMPLIES, then IFF.
  • Gate symbols follow whichever standard the header toggle is set to: ANSI/IEEE Std 91-1984 distinctive shapes, or IEC 60617-12 rectangles.

Sources

  • ANSI/IEEE Std 91-1984, Graphic Symbols for Logic Functions
  • IEC 60617-12, Graphical Symbols for Diagrams — Binary Logic Elements