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Circuit Description

A demonstration of the TTL-series 7400 and 7486 NAND and XOR integrated circuits.

This applets shows two typical members of the TTL-series family of small-scale integrated circuits (SSI). The 7400 integrated circuit contains four identical 2-input NAND-gates, while the 7486 circuits holds four identical 2-input XOR-gates. Similar circuits exists for many of the remaining basic logic functions; for example, the 7408 circuit holds four 2-input AND gates, while the 7405 circuits holds six inverters.

The symbols used in the schematics are based on the pinout of the actual gates (top view); the inputs and outputs of the gates are at the same pins (so that developers could remember the pinouts better).

The wiring of the 7400 circuit on the left again demonstrates de-Morgan's law and realizes a two-input OR-gate built from a NAND-gate with inverted inputs. Note how the 2-input NAND-gates are used as inverters. Click the A and B input switches or type the 'a' and 'b' bindkeys to control the circuit.

The wiring of the 7486 realizes a five-bit parity generator built from four XOR gates. Click the input switches or type the '0'...'4' bindkeys to play with the circuit.