JCDaly Header

Logically no change is occuring here.
By DeMorgan's Thoerem, the last state
is the same as the first state.

Digital Demo

In this demonstration we verify DeMorgan's theorem for Boolean logic. DeMorgan's theorem has two forms,

Use the digital integrted circuits provided to build the circuit shown below.

Use a value of 5 Volts for VCC and about 5K for the resistors. With 5K resistors the current through the LEDs will be about 1mA when the logic level is high.

When the switch is closed A will be at 5 volts. This is a logic high (1). When the switch opens, the A node is pulled to zero volts by the resistor. This is a logic low (0).

Determine the data values for the truth table shown below.

Truth Table
NOR Gates
SN7402N Quad NOR Gates

AND Gates
74HCT04 HEX Inverter Gates
74HCT08 Quad AND Gates

Properties of the integrated circuits are given in their data sheets.

74HCT08N QUAD 2 INPUT AND GATE data sheet
74HCT04N HEX INVERTERS data sheet
SN7402 QUAD 2 INPUT NOR GATE data sheet
74HCT00N QUAD 2 INPUT NAND GATE data sheet