Buffer vs Inverter: Understanding the Key Differences

This page compares a Buffer and an Inverter, highlighting the differences between these two logic gates.

Introduction: Both Buffers and Inverters are logic gates, but their functionalities are inverse of each other. Other common logic gates include AND, OR, NAND, NOR, XOR, and XNOR.

Buffer

Buffer

A Buffer logic gate doesn’t actually perform any operation on the input signal. Instead, it primarily increases the drive capability of a logic circuit, allowing it to support a larger number of fanouts (the number of other gates it can drive). Additionally, it can be used to boost a weak signal source.

As you can see in the truth table (implicitly described below), the output is directly proportional to the input:

• For input = 1, output = 1
• For input = 0, output = 0

Example IC: 74VHC244

Inverter

Inverter

An Inverter logic gate produces an output that is the inverse of the input value. This is the key difference compared to the buffer.

The truth table reflects this:

• For input = 1, output = 0
• For input = 0, output = 1

Interestingly, two inverters connected back-to-back can function similarly to a single buffer gate. Inverter gates are commonly used with basic logic gates like AND, OR, and XOR to create their inverted counterparts: NAND, NOR, and XNOR, respectively.

Refer to the difference between AND vs NAND vs OR vs NOR for more information.

Example IC: 74VHC04