7400 Family Truth Tables

Basic logic gates are fundamental building blocks of digital circuits, performing logical operations on binary inputs to produce a single binary output. The seven basic logic gates are: AND Gate: Outputs true (1) only when all inputs are true. Symbol: AND Gate Symbol Truth Table: A B A AND B 0 0 0 0 1 0 1 0 0 1 1 1

OR Gate

Outputs true (1) if at least one input is true.

Symbol: OR Gate Symbol Truth Table: A B A OR B 0 0 0 0 1 1 1 0 1 1 1 1

Tri-state outputs (for multiplexing outputs)

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In a 7400-series integrated circuit, the main difference between a tri-state output and a regular output lies in the ability of the tri-state output to assume three states: high (logic 1), low (logic 0), or a high-impedance state (open circuit). This allows the output to be effectively disconnected from the rest of the circuit when not actively driving a signal. Tri-state outputs require an additional "enable" input to control whether the output is active or in the high-impedance state, providing flexibility in signal routing and preventing short circuits when multiple devices are connected to the same output line[1][3]. Regular outputs, on the other hand, typically drive signals actively without the option to disconnect from the circuit.

The tri-state output's ability to enter a high-impedance state makes it particularly useful in scenarios where multiple devices share a common output line, allowing only one device to drive the signal at a time while others remain disconnected, thus preventing signal contention and ensuring proper communication within the circuit[3].

Citations: [1] https://www.electronics-notes.com/articles/electronic_components/logic-ic-families-technologies/7400-series-ttl.php [2] https://youtube.com/watch?v=OgV4tDxk7sY [3] https://forum.digikey.com/t/tri-state-logic-input-outputs/25183 [4] http://www.markbereit.com/rsrc/ccdig_74ls.html [5] https://en.wikipedia.org/wiki/7400-series_integrated_circuits

AND Gate Truth Table

A	B	Output
0	0	0
0	1	0
1	0	0
1	1	1

NAND Gate Truth Table

A	B	Output
0	0	1
0	1	1
1	0	1
1	1	0