Basic TTL Tri-State Buffer Circuit Example 2
Fig. 1

Basic TTL Tri-State Buffer Circuit Example 2


This variation of the earlier Basic TTL Tri-State Buffer Circuit Example 1. This differs in that we eliminated the SN74LS02 circuit.

This could be built from single quad 2-input NAND gate such as a SN74LS00 or CD4011.

Note the following truth table and conversion diagrams below.

Tri-State switch truth table. This illustrates a non-inverting output.
Fig. 2

Tri-State switch truth table. This illustrates a non-inverting output.

When the enable pin (EN) is LOW the output is floating.

Pin diagram SN74LS00 quad 2-input NAND gates.
Fig. 3

Pin diagram SN74LS00 quad 2-input NAND gates.

Connecting NAND and NOR gates to form inverters.
Fig. 4 Connecting NAND and NOR gates to form inverters.

using inverter gates.
Fig. 4 Connecting NAND and NOR gates to form AND and OR gates.

H-bridge motor control based on tri-state switches.
Fig. 5 H-bridge motor control based on tri-state switches.

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